diff --git a/docs/knowledge/basics/chain-spec/2xlarge.md b/docs/knowledge/basics/chain-spec/2xlarge.md
index d73a744..fc6b2cc 100644
--- a/docs/knowledge/basics/chain-spec/2xlarge.md
+++ b/docs/knowledge/basics/chain-spec/2xlarge.md
@@ -11,6 +11,7 @@ slug: /basics/chain-spec/2xlarge
 chain: 2xlarge
 num_validators: 342
 num_cores: 114
+preimage_expunge_period: TODO
 slot_duration: 6
 epoch_duration: 300
 contest_duration: 250
@@ -18,4 +19,6 @@ tickets_per_validator: 2
 max_tickets_per_extrinsic: 16
 rotation_period: TODO
 num_ec_pieces_per_segment: 18
+max_block_gas: TODO
+max_refine_gas: TODO
 ```
diff --git a/docs/knowledge/basics/chain-spec/3xlarge.md b/docs/knowledge/basics/chain-spec/3xlarge.md
index b3f14ed..ae88489 100644
--- a/docs/knowledge/basics/chain-spec/3xlarge.md
+++ b/docs/knowledge/basics/chain-spec/3xlarge.md
@@ -11,6 +11,7 @@ slug: /basics/chain-spec/3xlarge
 chain: 3xlarge
 num_validators: 684
 num_cores: 228
+preimage_expunge_period: 32
 slot_duration: 6
 epoch_duration: 600
 contest_duration: 500
@@ -18,6 +19,8 @@ tickets_per_validator: 2
 max_tickets_per_extrinsic: 16
 rotation_period: TODO
 num_ec_pieces_per_segment: 9
+max_block_gas: TODO
+max_refine_gas: TODO
 ```
 
 * The epochs are 30 minutes rather than the full hour of the toaster.  
diff --git a/docs/knowledge/basics/chain-spec/index.md b/docs/knowledge/basics/chain-spec/index.md
index 6b8cce9..a9d771c 100644
--- a/docs/knowledge/basics/chain-spec/index.md
+++ b/docs/knowledge/basics/chain-spec/index.md
@@ -24,6 +24,10 @@ The number of validators.
 
 The number of cores.
 
+### D `preimage_expunge_period`
+
+The period in timeslots after which an unreferenced preimage may be expunged.
+
 ### P `slot_duration`
 
 Slot time duration in seconds.
@@ -53,4 +57,12 @@ Constraint: $\mathsf{K} > 0$
 
 ### WP `num_ec_pieces_per_segment`
 
-The number of erasure-coded pieces in a segment
\ No newline at end of file
+The number of erasure-coded pieces in a segment
+
+### G_T `max_block_gas`
+
+The total gas allocated across for **all** Accumulation.
+
+### G_R `max_refine_gas`
+
+The gas allocated to invoke a work-package's Refine logic
diff --git a/docs/knowledge/basics/chain-spec/large.md b/docs/knowledge/basics/chain-spec/large.md
index 59d30df..dae1927 100644
--- a/docs/knowledge/basics/chain-spec/large.md
+++ b/docs/knowledge/basics/chain-spec/large.md
@@ -11,6 +11,7 @@ slug: /basics/chain-spec/large
 chain: large
 num_validators: 36
 num_cores: 12
+preimage_expunge_period: TODO
 slot_duration: 6
 epoch_duration: 120
 contest_duration: 100
@@ -18,4 +19,6 @@ tickets_per_validator: 2
 max_tickets_per_extrinsic: 3
 rotation_period: TODO
 num_ec_pieces_per_segment: 171
+max_block_gas: TODO
+max_refine_gas: TODO
 ```
diff --git a/docs/knowledge/basics/chain-spec/medium.md b/docs/knowledge/basics/chain-spec/medium.md
index 6896da4..5ddafd7 100644
--- a/docs/knowledge/basics/chain-spec/medium.md
+++ b/docs/knowledge/basics/chain-spec/medium.md
@@ -11,6 +11,7 @@ slug: /basics/chain-spec/medium
 chain: medium
 num_validators: 18
 num_cores: 6
+preimage_expunge_period: TODO
 slot_duration: 6
 epoch_duration: 60
 contest_duration: 50
@@ -18,4 +19,6 @@ tickets_per_validator: 2
 max_tickets_per_extrinsic: 3
 rotation_period: TODO
 num_ec_pieces_per_segment: 342
+max_block_gas: TODO
+max_refine_gas: TODO
 ```
diff --git a/docs/knowledge/basics/chain-spec/small.md b/docs/knowledge/basics/chain-spec/small.md
index 11668e1..d3cec2e 100644
--- a/docs/knowledge/basics/chain-spec/small.md
+++ b/docs/knowledge/basics/chain-spec/small.md
@@ -11,6 +11,7 @@ slug: /basics/chain-spec/small
 chain: small
 num_validators: 12
 num_cores: 4
+preimage_expunge_period: TODO
 slot_duration: 6
 epoch_duration: 36
 contest_duration: 30
@@ -18,4 +19,6 @@ tickets_per_validator: 2
 max_tickets_per_extrinsic: 3
 rotation_period: TODO
 num_ec_pieces_per_segment: 513
+max_block_gas: TODO
+max_refine_gas: TODO
 ```
diff --git a/docs/knowledge/basics/chain-spec/tiny.md b/docs/knowledge/basics/chain-spec/tiny.md
index 92a9594..f29e197 100644
--- a/docs/knowledge/basics/chain-spec/tiny.md
+++ b/docs/knowledge/basics/chain-spec/tiny.md
@@ -7,12 +7,11 @@ slug: /basics/chain-spec/tiny
 
 # Tiny
 
-A tiny spec for local testing.
-
 ```yaml
 chain: tiny
 num_validators: 6
 num_cores: 2
+preimage_expunge_period: 32
 slot_duration: 6
 epoch_duration: 12
 contest_duration: 10
@@ -20,6 +19,8 @@ tickets_per_validator: 3
 max_tickets_per_extrinsic: 3
 rotation_period: 4
 num_ec_pieces_per_segment: 1026
+max_block_gas: 20000000
+max_refine_gas: 1000000000
 ```
 
 Please consult a few other JAM implementer teams before changing this spec, as it is in use for
diff --git a/docs/knowledge/basics/chain-spec/toaster.md b/docs/knowledge/basics/chain-spec/toaster.md
index 7657313..e2c67ab 100644
--- a/docs/knowledge/basics/chain-spec/toaster.md
+++ b/docs/knowledge/basics/chain-spec/toaster.md
@@ -12,12 +12,16 @@ The full scale version that will be known as the "JAM Chain". All parameters her
 chain: full
 num_validators: 1023
 num_cores: 341
+preimage_expunge_period: 19200
 slot_duration: 6
 epoch_duration: 600
 contest_duration: 500
 tickets_per_validator: 2
+max_tickets_per_extrinsic: 16
 rotation_period: 10
 num_ec_pieces_per_segment: 6
+max_block_gas: 3500000000
+max_refine_gas: 5000000000
 ```
 
 The "full" name comes from the fact that full takes up the entire JAM "Toaster".
diff --git a/docs/knowledge/basics/chain-spec/xlarge.md b/docs/knowledge/basics/chain-spec/xlarge.md
index 07dbe09..1d109e0 100644
--- a/docs/knowledge/basics/chain-spec/xlarge.md
+++ b/docs/knowledge/basics/chain-spec/xlarge.md
@@ -11,12 +11,16 @@ slug: /basics/chain-spec/xlarge
 chain: xlarge
 num_validators: 108
 num_cores: 36
+preimage_expunge_period: TODO
 slot_duration: 6
 epoch_duration: 240
 contest_duration: 200
 tickets_per_validator: 2
+max_tickets_per_extrinsic: TODO
 rotation_period: TODO
 num_ec_pieces_per_segment: 57
+max_block_gas: TODO
+max_refine_gas: TODO
 ```
 
 * The JAM Toaster can support 5 XLarge configurations.