To lift the rear - use either an i.e. (later model 750/900) shock, which is slightly longer than the original, or an aftermarket unit, such as Ohlins, which has a ride height adjuster. Ohlins or similar (single rate) springs in the front will reduce a lot of sag, also lifting the bike a bit. Note - you may need to alter (or use a different unit) the sidestand, as with the stretched out suspension, the bike will lean over a lot more on the stand.
Go to the SuperSport forum, and do a search on suspension mods - that should give you some options.
I had a 1994 750ss. I too felt the bike could be a little taller.
Back when I had the bike, my mechanic who was spannering for a gent racing a 900ss, milled a short adapter block out of aluminium. This block was then able to be put mounted on the top of the shock, then bolted to the frame, it gave me about 12mm of extra ride height. just like an extension.
A couple of years later, I also saw an original Ohlins part that did the same thing. It was an extended eye link which was fitted as a direct replacement for the bottom rose joint. It was therefore adjustable from standard up to about 10mm I believe. Just my two cents worth anyway