Hello all,
Apologies for not following up on this thread. I don't check this email very much. In addition to the reply from atlas, someone else also emailed me direct with questions. Here is my update in case it helps anyone in the future.
I ended up with a Medeco M3 KIK cylinder that I've had installed & working for about a year now. I had to have it custom ordered as a 5-pin due to space issues. cledry mentions this above, but it was the bible that would be too long due to that z-looking bracket in the last picture atlas posted. I wasn't willing to risk bending the bracket outward as I would have been screwed if it snapped.
Finding a Medeco locksmith that would work with me on a custom order was more difficult than I thought it would be. Most just wanted to sell me whatever they had in stock. I needed a KIK that was both 5-pin and in satin nickel, which meant custom ordering. I finally found a mobile locksmith in my area that has been in the business for 30 years that would work with me.
My locksmith ordered the custom KIK as well as two deadbolts all keyed the same. The custom order took about 6 weeks to arrive.
I did a self-install. My locksmith gave me a recycled tailpiece that he thought might work better than the one included with the Medeco KIK...and he was right. The tailpiece from the factory schlage KIK would not fit the Medeco. The tailpiece included with the Medeco could be made to work, but it would require grinding the height down a bit to fit in the gearbox slot. I've tried to show what I mean in the picture below.
In the email I received from the forum member, the person mentioned looking at Protec2 and MT5+ in addition to the M3. I looked at those as well, but opted for Medeco for a few reasons. Medeco offered sufficient security for my needs, they had the finish I wanted, and they seem to have a much larger amount of dealers I can work with if needed.
As a side note, I think these multipoint doors offer great protection from hurricanes. However, I have to wonder if they are easier to break into than a traditional door for someone that knows where attack. I think you could remove the handle (via the set pin) and drill out the top and bottom of the faceplate. The faceplate should fall off at that point where you could remove the KIK. Some ball bearings dropped in the faceplate screw holes might help, but I haven't tried this. The faceplate screws might be too long for this without cutting their height down a bit.

