Butyl rubber glue, pretty easy to find a roll on ebay. But your existing glue should be enough (stick it back in the oven to warm them up and squeeze the lens and housing together).
You can do it in a day.
You need to calm down, note the " " BTW my HICAS is trying to kill me at 1/10 driving.
Also, I think Shuto Kousoku 2 came out around 1990, no idea if they had HICAS delete kits back then.
Lots of people have fit the R33 GT-R wheels with just a guard roll. I can't remember which tyre size, but you can run 235-255 depending on your setup.
As for distances, measure yourself? It'll probably be quicker.