I'm taking Alpha Male and Carbolin 19 together, not quite TRIBEX, but close enough for conversation.
As Bigaroo mentioned, the TRIBEX goes on an empty stomach. I realize this is hard to do if you are bulking, as an empty stomach is something you avoid having. I take if first thing in the morning and about 1.5-2 hours after lunch. The Carbolin 19 I take with breakfast and my afternoon snack. I avoid taking it with dinner, just to be sure I don't get the stimulant effect in the evenings.
Good stack, and along with hard work and big eating, it makes noticable results.
There is no reason you cannot take them together, and both will help. The only reason I can think of not to (besides medical issues) is to experiment to see how one or another works for you. But you will get a bang for your buck taking both.
Just to clarify, you mentioned cycles a few times. If you are refering to supplement cycles, go for it. If you are refering to an AAS cycle, I am not the best one to answer this, but common sense tells me to hold off on both until your cycle is complete and use this with a smart PCT and/or post cycle maintenence.