Here's an idea: put a zip tie or something on the metal shaft of each shock, then find a hill or loading dock or something to flex 'er out, until the opposite wheel is airborne... then see where your zip tie is. That should at least give you a rough idea of available shock travel, maybe have a buddy watch who can yell at you if you start to bottom out a shock.
There are really only a couple things that will limit your travel- your springs will stop flexing (and there's not enough weight to get them to arch further) or something smacks into something- like a tire on the fender, or axle on a bump stop, tie rod on a driveshaft, shock fully compressed, etc. find out what's limiting your travel, then worry if you need to limit it further.
99 uzj100, gx470
05 525EXC, 01 XT225, 07 TTR90, 07 CRF50