I use
the Microverb 4 which is basically about the same with
a Mackie Dfx12 and have spent a year or two trying to find the effects needed. After trying half of the 100 efx I use about 3 on the verb4 mainly because they are together and easy to switch.
97 Tight room and slow stereo chorus
98 Bright hall with a 1/4 note delay @ 108bpm
99 Large room and slow flange with feedback
Each depends on the type and tempo of the music On the dfx12 I generally use med plate or large plate to put reverb type efx in vocal The large plate will put more echo in and if I am doing fast rock tempo and dont want echo I'll use gate or even reverse gate on the dfx12. On old rock I'll use spring or phasor. Spring is the oldest efx used with the fifties and sixties stuff and is good with chorus. All efx depend on the reverbs or acoustics where you are playing...
When you say big sound I'm not sure if you want richness or the auditorium or stadium type echo.I usually try to run efx right up to point of just starting to echo..
Using chorus with plate or flange or combination of all will give an awesome "big room sound" and the amount of efx will tailor the size of the room better than reverb alone. On a song like Folsom Prison Blues I'll use 98 and have the decay and rate adjusted to give a slapback 1 type efx on the bass. 99 works good on all rock and gives that "broadcast" type sound and works with about any efx on the Mackie
These are just some basic things it would be a lot easier to show you but the best advise I could give you is play cd's with the type of music that you are trying to efx and see what works with your system and the acoustics where you are playing.
On another thread I have a couple of downloads availible to show what I do with vocals but it is one of those things I'll never be satisfied and will spend many more days on this....