I use a bit different setup. No regulators at all. I use 2pcs 5 cell NimH packs. For the Elan I would go with 2000Mah each. Dual switch harnesses and plug the "extra" battery in an unused servo port or thru a "Y" harness on the retract or brake channel. I've seen to many failures due to inadequate regulator rating. No need to isolate the packs either! I recommend the NO BS elite cells at 7mh. Keep it simple.
The Hitec 5645 would do fine...BUT the JR8411's will give stomping performance!

Dave