of course the do it on the year bike i have...when it rains it pours! i will play around with things and post the findings.The problem is that during mid-year in 1991, Kawasaki changed the ZX-11's carb set-up. 1990~1991½ have 155 MJ while 1991½~1993 have 140 MJ (all those numbers being OEM Keihin jets).
As a rule of thumb, MJ are usually enlarged by 5 or 10 points. But jet kits also comes with after-market needles that are richer and ajustable. If you only use larger MJ, you will possibly be too lean in the areas regulated by the needles. You can shim the stock ones but it could be not enough.
Each bike react differently to a pipe. Some needs larger than OEM MJ and some works better with stock MJ. While a similar bike's set-up is a good starting point, you need to fine tune your own ride anyway.