Well, I always split the inject and put 1/2 in each bi. Besides I put tren in my bi's and it was great. It made my bi's get extremley pumped on arm day and it also made them hard as a rock for the whole cycle. For most of my schedule my injection scheme looked like this for tren(cycle was 12 weeks):
day 1 long head of bi's
day 2 short head of bi's
day 3 the outter part of the tricep
day 4 The inner part of the tri's, I did this by holding my arm straight up in the air and then would inject. It was kind of strange at first to inject with a needle hanging upside down but I got used to it. Also this spot would get sore the easiest.
*Bis would get somewhat sore when I first did them but adjusted the fastest and now I can inject anything in bi's with absolutley no soreness. The outter part of the tris shot was almost zero pain also.
*I also did a few brachialis injects during my cycle to give them a try and everyonce in awhile I'd do quad injects just for someplace diffrent.