I'm close to finally floating my Ultra Pierre and have a question on brakes for my trailer. The donor trailer is a 1974 dual axle in great shape. Trouble is, in '74 they didn't have to have brakes on dual axle trailers (the laws have changed since then). The axles are 3500Lb each and the boat should come in at about 3800 gross (so there is plenty of capacity). The axles have flanges on them for mounting brakes so all I have to do is buy the parts

.
I have dragged trailers around for years most were single axle without brakes, some were tandem axle with surge brakes and drums. I am getting some advise for electric brakes in place of hydraulic surge type but don't have much experience here.
Application is mostly fresh water, distances are under 150 Mi radius hilly to mountain terrain.
Any opinions on using electric brakes on a boat trailer? Which Brands are best? If hydraulic surge, drum or disk?
Any and all feedback is appreciated.
Thanks,
Mike Morasci