Basically, the Ironman kit will get you about 2.25". 245/75-16s will clear with that much lift. Preferably, you want 2.5" to accommodate all tread patterns etc. Add the 1/4" top plate, and you have 2.75" of lift. Plenty for the tires. You can then add the 3/8" clevis to get about 3.25" of lift.
HOWEVER, after you go about 3" or so you will need a-arms. Were those included?
If not, I'd add the top plate. Then if you decide to get a-arms at a later point you can add the clevis lift for more height. I suggest this route just because it's easier to add a clevis lift than it is to drop the whole spring assembly and add a top plate.
For the rear, I'm not sure exactly how ironman springs sit. I'm assuming close to OME. If that's the case, 1 rear iso per side will put you pretty level with only the clevis or top plate. If you do both, you should add 2 extra per side. Make sure you add them to the top.