you can pin the test and tren in dif locations if you want. if you're pinning in glutes or quads then don't bother but obviously for other smaller muscles you\ll need to do seperate injections since they can't handle as much. by the way, test prop and tren ace are my current cycle.
but you can shoot tren OR test with a slin pin..that's what i do when i pin anywhere other then quads or glutes. If you need help with other locations you can go to SpotInjections.com
but a quick list of what i use is right/left: delt, tri, bi's, pec, quads, glutes. that's 12 injections worth....and that's not inclluding other spots you may consider pinning but which i wouldn't recommend ie. traps, calves, lats. .... eyeballs. jk. just check that site out.