BJ ill try to answer your questions
1) Minnkota all the way. I have owned both and all three of the motorguides i have owned gave me nothing but grief. Blown boards, armatures, snapped cables etc. The minnkotas i have owned have taken every bit of punishment i know how to dish out ot a trolling motor and have just worked. It also dosent hurt that the mionnkots are betrter on batteries, are quieter and superior in the weeds. thats my .02 btw the pro series with lift assist is SWEET!!!
2) I would go with 4 batteries. Your trolling system is only as strong as the weakest battery in the system. The starting battery would be the weak link. I also dont like dual purpose batteries for trolling duty. If it was my boat i would go with 3 deep cycle only batteries( trojan scs for me) and a dual purpose for the starting/ elcetronics/ pumps.
3) I have read lost of good things about the stealth on boards but heard bad from people i trust. The guy i buy my trolling motors and batteries from says the stealth will kill batteries. He sold them for a year and had lots of issues with them. Also a guy in my club had one and he had problems too. IMHO if you have good quality batteries and a good charger( guest) you should never run out of power. I can run my 80# minnkota in big wind all day and never even have a hint of power loss. Running out of power has never been an issue for me with the Trojan batteries an Minnkota motor.
I hope this helps.
Lamar, The reason fto run a 36 volt troller is thrust. If i remember correctly BJ is buying a bigger boat and im betting he wants a 100# tm and i dont blame him, i would too. A 36 volt motor wll run longer on a big heavy boat then a 24 volt one will with less thrust on the same boat. I run a 80# on my 882 and there are days i wish i had a bigger TM. Sure i can run all day with my setup too but i doubt i would on a 20' but a 36v 101# would just fine. Just the same as the 55# you run on your 185 would most likley not last all day on my 882.