You're going to want to buy some time on a dyno and some carb
bits to help you tune things. The strombs are not bad carbs but
they are not adjustable at all. This is a good thing most of
the time since you know that nobody else has "adjusted" them
but in your case you may have some issues.

I would fiddle with stiffer piston return springs and maybe
consider putting notches in the needles (have a spare set of
needles on hand.

I wouldn't do any of this without a dyno and an exhaust gas
reader to tell you if you're getting anywhere near optimum
mixture. You're going to want to see how the mixture looks
at WOT and part throttle at a bunch of different RPMs. Only
muck with the carbs after you've got *everything* else (timing
/valves) set to optimum. If you're planning on sniffing the
exhaust and reading plugs you should probably just give up now.

What does your cam maker say the valves should be adjusted to?

Ideally you're going to want to replace the carbs and put on
some form of FI; I'd go for a megasquirt system in your position.
chris