Pretty sure I've posted this before, but to re-iterate: the Speco T7010 underwent a drastic re-design a few years ago; I have no idea why they kept the same model number since it's different in every possible way. Nevertheless, here are the connections. I would go for high impedance, high sensitivity headphones and the new transformer, given a choice. The Quickie is not powerful, it's just fun, cheap, and sounds good. I'd look for 95dB/mW or greater.
FWIW, high impedance works well with Crack in case one is thinking of an eventual change. Crack does NOT need highly sensitive phones!