Trenbolone base contains pretty much 100% tren since it doesn't have an ester attached to it.
Trenbolone acetate contains about 83% tren because the acetate ester takes up about 17%.
Trenbolone enanthate contains about 68%.
Parabolan has the hexahydrobenzyl carbonate ester attached to it and the potency is about the same as the enanthate.
I'd choose tren ace over the other esters. Mostly because it's usually 100mg/ml, so it's easily injected with no pip most of the time (depending on lab). Injecting EOD is ok..
Tren base has a very short half life since it's esterless so it needs to be injected frequently and what I've heard, it hurts like HELL!
Usually labs can't go higher than 50mg/ml with tren base.