Cannabis really brings out the artful complexity of LSD visuals, I wouldn't trip without it, but I also am very cautious not to use too much. You don't need much. People tend to overdose cannabis anyways, since everything is uber potent now.
I have done LSA several times, and cannabis is really key to being able to enjoy it, it really brings out the visuals.
LSD doesn't really need any help in that department, but it does make the experience more enjoyable for me. It tends to give some "personality" to the visuals as well, in my experience. It helps add extraneous meaning to the nonsense, but also adds to confusion and amnesia.