Craig, i do run the scs 225's. i have a 24 volt setup and i use a 27tm for my start. From what im told you can also run a scs 225 to start the motor if need be.
I got mine from Nissitissit trolling motor service when they were in pepperell, but they have since moved to NH. There is a place in worcester that sells them also, its an industrial battery place on rt 20. If you go on the trojan battery website they haqve the contact info. Northern bass also sells them.
If you go with trojan you are making the right choice for sure. They are goiugn to cost you more(i have heard the price went up a bit due to the cost of lead) but you wont have all the same grief you get from the wally world ones at all. The Trojans will be dependable and perform awesome. Im going on season 5 with mine and they show zero sighs of slowing down. I fish a lot and use them hard too.