Blade tension..... My mill doesn't have any fancy gauge to register tension. In my first year or two of use I was over tightening the band, this caused failure in the bearings of the band wheels. Since then I have had bearing failure but from normal wear. 2 years as apposed to ten. This is how I tighten my band.

Place a band on the wheels and rotate it to track the band on the wheels. I do this by cranking the engine via the key switch, I have a secondary switch to prevent the engine from starting. With that done I slowly tighten the band watching between the two wheels and the slack in the band, at the top, not the bottom due to the restrictor bearings getting in the way. You should see a clear point where the band stops movement, that is key, even though you could still tighten, at that point I simply tighten a 1/4 turn more and lock it down. This quarter turn is specific to my mill, your tighten device may be slightly different, so it should be just slightly more tight, your judgement call. I believe it would be due to the size of threaded rod the tighten device is made of, mine is about 7/8" rod.

Things to keep in mind. As the band heats up it may need to be retightened. But not usually, the band should run cool, if all is set properly, that would be set and sharpness, these are important. New band may stretch a little but not enough to demand retighting with first use, the next time you use that band you may tighten it to its new state. If you are seeing wavy cuts or dives or rises in cut it is more due to set and sharpness and tooth angle and even species of wood. Knotty wood is known to wave.

As for the v belts I can not comment my band wheels are coated in a poly material and never need tending. I hear v belts can be tricky. Have you talked to these people?
http://www.suffolkmachinery.com/index.html