As i said the gen 2 chassis requires fairly major modification at the "y" section in front to clear the exhaust outlet, Service honda make up a new section and weld it in, however it is possible to cut out the factory section and modify to spec and re-weld in. You have to make sure you use a compatible alloy that is ok to weld, I used 6061 I think. If you do a search on alloy grades you will find the info.
Your bottom engine mount shouldnt need modifying, it should bolt straight in once you have clearance at the front, dont go cutting your bottom mounts off.
Use 500 swingarm pivot spacers with the 250 pivot bolt, you will need to machine a small amount of material of both spacers to fit.
You will have to make new top mounts/plates using 8mm alloy plate, I started with a cardboard version which i shaped and drilled, then flatten it out on the alloy plate, scribe a line and cut out, you can then bend the plate using the 250 plates as a guide.
Hope this helps.
Cheers
Red