Some preps can be used internally and externally, but check with your prep manufacturer (or dealer) before doing so. Some do not work well inside. Our prep program is pretty simple: One product for internal - can also be used externally Pink Panther), one product that softens and adds a ton of bite (Monster Bite), and one product that adds bite but does not soften (Black Bite 2.0.)
Those three will cover 95% of the track conditions you'd see.
33's prepped down are generally faster than 22s, especially on larger tracks, but I know there are tracks back in your part of the country in which 22s are the best choice (Ken's track may well be one of those because of the size, moisture, and soft surface.)
Personally, we have eliminated all of our "in between" compounds (22s & 44s) from our team's inventory. If it's a slop-hole, then we've got 11s available. We've got 20-25 sets of 33's cut & prepped all over the spectrum that we use the majority of the time for Burris spec tire races, and a couple sets of B55s (just in case.) Where we race locally on Burris, I could tell you within a set or two what we'll be on in any given class each night. When we travel, our trailer cannot hold enough tire choices. One thing I have learned about bigger $races/tours/series/etc. using a spec tire (Burris), is that you never have enough tires worked and with you at the track. For weekend racing where you run the same track, same class, etc every week (and the promoter works the track consistently without throwing the occasional curve ball ie calcium, water truck broke down excuse, etc.) you really don't need a large inventory of tires (spec or otherwise) since you know what you'll need. At least with our preps, if you need more bite, you wipe more coats...if you need less bite, you wipe less....doesn't get much simpler than that.