1-t transdermal is 1-dhea. two steps away from 1-test.
1-ad transdermal is (depending on which version you found) either 1-androstenediol (newer) or 1-androstenedione (first version) either way, this is one step away, and a direct pre-cursor to 1-testosterone.
either way, the 1-ad would be better than the 1-dhea. esp if it was the diol.
conversion rates dont mean a hell of beans, and that's straight from the man who released the "in vitro" conversion rates from his creation (4-androstenediol), Patrick Arnold.
conversion isn't a one way street, but can go back and forth the life of the pro hormone. not to mention the limited number of available enzymes to make the needed conversions.
If I couldn't get 1-androstenediol, i'd go with 1-dhea, but you can still find 1-andro-diol easily, for about the same price as a bottle of 1-t.