Troll motor speed - 40 lb vs. 70 lb thrust

I have a question on trolling motor speed. For crappie long lining I usually have a speed of .8 to 1.1 in speed #1 on my minn-kota edge 40 lb. I have a 14 ft Jon boat. Considering a 70 lb thrust motor but concerned about speed for long lining. I assume more power, more speed, so if that's the case this may been too much motor for my boat when long lining. I also fishriver current a lot and the 40 lb doesn't get it much of the time, so been considering a higher thrust motor. So there are really two questions....slow speed of a 70lb thrust and he river current issue

Anyone with experience in this sort of situation? Would like some advise before I commit to a purchase . I may have to live with what I have, Edge 40

If you get a 70#'r with variable speed control and not just a 5 speed, then it may be the best of both for you. could always use a drag chute to help slow it down as conditions warrant.

Yup, a variable speed motor would solve your problem.