I wrote about 1,700 words of "extra" material for the book tonight. It's looking like II Crimsonstreak will be in the range of 94,000 words. Main story is 83,000 words; I have about 11,000 words of stuff for the appendices.
For reference, the first Crimsonstreak novel has 72,000 words for the main part of the book and 23,000 words of material for the appendices in the back.