Any of the D24 series work real good. They fit between the ties. Drill a 1/8" hole in the roadbed and push them it. Just mount 1 on the inside of each rail. They work with any code rail and on curves. You can put 2-3 in a row for a longer uncoupling area. No track modification necessary.
(can’t beat the price!)
I use the McHenry delayed action uncoupling magnets that mount under the track so there’s no need to pull ties or concerns about height between the rails. They are a bit more involved to mount but it’s not that hard.
I cut a section of the cork roadbed out that’s the length of the magnet. Then with a rotory cut off disk, I’ll cut slots in my subroadbed in 1/4" deep horizontal and vertical slices where the cork section I just removed used to be. Then i’ll take a wood chiesel and remove the material I just finished cutting the slots into with the cut-off wheel and then glue the magnet in place positioned so that it’s even with the cork roadbed. (i’ll use some cardstock strips under the magnet to level the magnet evenly with the roadbed if i cut too deeply into the sub roadbed.) I’ll then lay the track over the magnet and use spackle to fill in and create a new roadbed taper that replaces the section of cork roadbed that was removed for the magnet installation. The McHenry magnets are more powerful than Kadee’s because they are so much bigger and work very well for rolling stock uncoupling…chuck