2099 Unlimited #1 (second story)
2099 Unlimited #2-6 (first story of each)
Spider-Man 2099 #25 (8 page back-up)
Ravage 2099 #25 (8 page back-up)
Hulk 2099 #1-10
last six pages of 2099 AD: Apocalypse #1 (optional)
Hulk 2099 does appear on the cover of all 6 issues of 2099 Unlimited that he appears in.
The biggest question about this book is what to do about the Apocalypse one-shot at the end. Hulk 2099 #10 has a “to be continued” note pointing to that issue. It does have a pretty decent cap for the series, but only the last few pages actually involve Hulk 2099.