Many times the female and male won't fit in the male's tub together. I've heard of some people who have had success putting the female in with the male though. I'm not sure it makes a huge difference from a breeding success standpoint, but logistically I find it easier to move a smaller snake into a bigger tub rather than the other way around.
I just put a female into the males tub this morning and they are already locked. It was a full size tub though. I guess it depends on what you think may be the least stressful.
I had been trying to get my snow male to lock with my ghost female for several weeks with no success. Tried putting her in with him and had a lock over night. You have to try everything.
I would have thought the female would have got more stressed from moving from her enclosure as in the wild is it not usually the male that looks for thw female or am I wrong here?