After some time familiarizing myself with the options, (and realizing the mobile site is severely limited in the amount of information it shows about each product, hence why I couldn't figure out what style connector each battery had) I settled on this
http://www.batteryspace.com/cu...2-5mm-male-plug.aspx
and a charger to match. With shipping (and an extra barrel plug to install on the engine) it cost just over $70.
We'll see how it works when it arrives.