how to use test prop with other steroids

[25homes]

My stats are pretty modest I’m 6’4” I’m 218 lbs with around 16% body fat and I’m 48 years old
interested in trying out testosterone propionate and I would like to mix it in the same syringe to cut back on post injection pain
although this is not the first time I’ve used it this will be the first time I’ve actually used it in a stack.
What advice can you give me on whether I should add it to equipoise or primo?
I’m most intereted in putting on moderate bulk.

Test is test