The number of coils in a spring is not really indicative of the "strength" of the spring - there are several other factors that also play a part, diameter of the wire used, diameter of the former the coil is wound on and pitch of the windings also play a part.
A quick & dirty way to look at it is to compare the difference in weight of the two vehicles - the V6 model weighs roughly 175lbs more than a 4 cylinder and the bulk of that difference is in the engine & transmission so largely concentrated towards the front.
Before going with OME I considered using the V6 springs to compensate for a winch bumper that has yet to be built & fitted - if & when that time comes, I'll just upgrade the OMEs.
I'd leave the spacers in, my train of thought being that the spacers were sized for a vehicle without the additional front end weight, and the springs are going to be used for that.
Before you fit the V6 springs, put them side by side with the originals, I'm betting they are no taller (no significant difference in free length)