Quoted from Erik:Which mezelmod target splints work with the ZUSE targets? I understand there are two piece and one piece
They are based on the width of the target. Looking at an image of the targets, it looks like three single piece and one two-piece (for the S).
However, I think only the Z and U move to block shots though, so you probably don't need to splint all four targets. I don't have game to look at as reference, but I'm looking at images online.