Tons of choices for sure. Going from the old Keller style pedelum sight to a fixed sight I don't think will be an issue. Just may take a while practicing to sort of get the feel of not having a bit of "distance" compensation that a pendelum can provide.
I would be careful attempting to use more than 3 sight pins. For me a sight picture becomes mighty crowded mopre than 3 pins. In fact when I hunted with a bow, I used a single pin ... probably for 20+ years. Usually with three pins, and plenty of practice it is rather easy to cover the kill zone from out to 40-45 yards.
I gather from your use of a Keller that you hunt from an elevated position most of the time. I suggest that you practice with the fixed pin sight from an elevated set-up as well.
I'd chose a bright, fiber optic sight. Be careful to examine the design carefully for ruggedness.
I have found that the "red" will fade out sooner in low light than green or yellow. So if you are going to use multi color, which I suggest for ease of selecting the correct pin quickly in the field, I'd use the "brightest" for the most "usual" distance .... which I'd think would be your 20 yard pin. Could just be my eyes, so test which color is brightest for your No. 1 use pin color.
Also I found a large peep more suited for hunting conditions. The larger diameter allows more light and that counts late in the p.m. down in the deep woods! Some folks prefer the small diameter peeps. It is just a matter of personal preference.
I am not a fan of "distance adjusting sights" because eventuially there will come a situation when you will not have the luxury of enough time to be able to make an accurate distance read and tweak the adjustment. Another issue is that if you hunt in snowiy/icy conditions, these can ice over making it tough to break free quickly and quietly so that you can make the adjustment. Plus these present one more level of complexity. I am not bashing these type sights. They work great for sure, but my preference is towards simple and rugged.
One thing you will notice going away from the Keller is the pin sight will be a ton quieter. All of the Kellers that I have experience with had a rather substantial "rattle" on release due to the pivot pin, swing frame design.
Good luck and have a great season.