I think with regards to the fuel ratio, i think alot of people overestimate the VE of the old 4.2's when they are doing fuel calcs. You have to remember the standard manifold on these things have more than 30% difference in flow between the best and the worst. So using a VE of say 72% might be applicable to 2 of the cylinders, the other 4 would be done considerably on that.
I should have done a coast down and measured engine torque, but its not something i really ever bother doing, i just measure before and after in % and thats good enough for me.
I have found that particular setup still has a good amount of room left for the power hungry.
The dyno graph below is with the same turbo, slightly larger intercooler core.. but no other differences what so ever. Except more boost and more fuel, still no smoke though

Was about 20-21psi and 18:1 while on boost. Was very interesting to note, going all the way up to 28psi on this vehicle made no more power and did not lean out the fuel ratio at all. The little turbo is just well out of its efficiency range past about 20psi.

Sorry for not having fuel and boost on this one, I would have to dig it up as this is quite a few years old now.
Red graph is standard, Blue is turbo/intercooler/exhaust/tuning etc.., green is with water/meth injection on.
Ramp rate is road speed per second of acceleration. Generally take your number of say 070, divide that by 10 and it give K's per second of allowable acceleration.
The dyno then measures how much force it must apply to the retarders to stop the vehicle accelerating any faster than this set rate.
So the lower you set it, the more load the engine is under.