We have three QH's an 6 other various Horse.
Our Little Guy, 14-2 uses a Reg QH tree, he is 5 now.
I suspect the Simco you mentioned was a Semi-Qh Tree, many are as standard, a semi-QH tree will pinch for sure.
The other Saddles sound like they are Full QH, they would be wider and sit down on the withers, also the bars are longer, which cause the skirts to be longer, neither works well for little guys.
I say little guy, because our other guys are 15-2 and 15-3
May all your Trails be happy and safe ones