In my opinion, fully panned double tracked guitars give the best foundation for wide stereo usage. This is because fully panned sources are truly independent and does not leak into each other, which in turn means that any discrepancies or differences between L/R will always be at their widest point. What you really need, is hard pans and then pull just certain elements back towards center. For this I'd recommend using a multiband stereo tool. GMulti, which is a multiband compressor that allows you to bypass the compressor function and use its built-in multiband stereo widener / contractor.
Stereo enhancers are some pretty cool tools, but their usages are often limited. If a stereo source originally is very little widened, you can with good results use it to widen them out. Works wonders for certain drum overheads and room mics because they are often recorded in stereo and the channels are dependent of each other.
However, when you add stereo enhancement on max panned guitars (which are dual mono and independent of each other), you always subtract from their original spot, and the processed audio from one channel always go into the other channel. It is not possible to further widen a 100% panned source without it leaking into the other channel.
With that said, there is the matter of aureal perception are two ways of processing stereo. The first version is basically like a stereo panner that doesn't add copies of the audio but rather sends the original audio out to their respective sides. Useless for rhythm tracks as you already can pan them max manually. Useful for stereo tracks that are originally locked closer in the stereo field. The other version is the delay (haas effect), which I'm assuming is the topic here. Because of the induced haas effect created by stereo enhancers, it will sound like the audio surrounds you. What really happens is that the processed audio is a copy of the original source but delayed and panned in opposite direction.
What you are proposing is to have the original source only slightly panned and then add stereo processing that will widen them further? Here's why I don't think it's a good idea, or rather, doesn't really give any benefits:
Stereo processing that uses delay pushes a processed signal towards the other channel, starting from center and working its way to the opposide side.
This means that if you did a 50% widening, the processed audio is pushed 50% towards the other side. For instance, if one the original sources was panned 40% left, then the processed audio is pushed 20% right. If the original source is 60% left, the processed will be 30% right.
With 100% widening you are panning the exact number in the opposite direction. Most enhancers go way beyond 100% and will eventually "loop back" into the original channel. When this occurs, you get phasing, because the audio is essentially a copy of itself in the same stereo field. Some enhancers can add slight coloration to the processed signal to dampen the phasing effect.
So, let's say that your original track is 50% panned, and you stereo widen it with 150% to achieve 100% to the other side. This is very much the same if your tracks were initially 100% panned and if you had only 50% widening. The difference is that the former has the "copies" farthest out with the original source closest to center. The other difference is that the copies, which are furthest out, are delayed by the amount of milliseconds you set in the stereo tool. If the copy is delayed 10ms, then you'll hear the original slightly panned audio first, and the farthest out copies 10ms later. Not easily recognizable, but the delay is there.
With all of this said, do some experiments. If you don't use the delay feature on the stereo enhancer, then you are basically just panning the audio further to their respective sides (as opposed to the opposite channel by using delay / haas). With this you're back at square one. I've used stereo enhancers on rhythm tracks in the past, but not anymore. There are more delicate ways to increase perception of a wider stereo field. One way is to actually pull certain frequencies (50-80+ Hz, generally low-end boom) innwards using a multiband stereo tool like GMulti. Another way is to quad track with mixed panning, which always produces true and differential sources in stereo. Whatever you do, always make room for the rest of the composition.
Edit: Added some clarification.