Well here is my experience with trying slingerland in place of teardrop hoops. I refinished a very out of round and beat up teardrop snare with not very nice hoops. I bought a set of really nice slingerland snare hoops expecting to be able to do a swap on them and no luck.
I think the fact that the snare was out of round and I have some weird thing going on with the lugs which some look to be drilled off center and they don't have spring loaded inserts made it impossible to use the Slingerlands. Also the fact that a teardrop snare is only 4.5" deep with hoops sharing the same lug doesn't allow any flexibility of the shell. Even with the actual sonor hoops I couldn't tighten one side before installing the other head.
Now on to the question of a 12" tom. I think it will work because I used a MIJ hoop which was very close in style. I eventually found a pair of 60's sonor hoops(which is really funny because the guy I got them off of has the same ebay user name as you).
I've done a lot of searching over the years for sonor parts do to my obsession of phonic and teardrop drums, it's hoops and tension rods that are the hardest to come by. Drilling out an oval shaped hole has become quite common for me using non-sonor parts! I use drill bit size 9/32"(.281") or 7.14mm. It's a little bigger than 1/4" so the slotted screws fit nicely through them.
Good luck, I hope this works for you.
Gary