The difference here is that the sus has different esters. The propionate in the sus (small amount) will act faster and it also happens to feel so nice and smooth the next day

lol, jk.
If he has a burning desire to use his sus, I would use it at the beginning of the cycle, mixed half and half with the E. I'm not suggesting that's correct or whatever, that's just what I would do. Maybe do his shots 3x a week while he's still mixing the sus and drop to 2x a week (while still maintaining the dose) after it runs out.
Any vets disagree?