So I tried it! How hard can it be?
As it turned out, very hard.
First attempt: Launch from LC-19. Titan II phase went well, Orion 50SXL spun out. FAILURE.
Second attempt: Launch from LC-19 again. Titan II phase went well (again), Orion 50SXL spun out (again...). FAILURE.
Third attempt: Went full Taurus mode and stripped Pegasus of its wings and fins. Looks kinda like Thor-Able. Orion 50ST did not spin out, and placed Telstar 1 in a LUNAR ORBIT. (yes, it is really that powerful, and that's with 50% fuel on all stages and LR87 on 75% thrust btw!)
Overall, sound launcher tbh, just need to do it Taurus style