I don't have any of those but I do have Tract Toric 12x50 and 15x56, so mine are comparable to each other. I find the 15x56 much heavier and longer. Yes, you can see detail better at distance if you have a rest to help. 15x56 cost quite a bit more of the same quality and the binocular case has to be a lot larger. I bought the 15x56s because they were offered a very good price.
I think 12x50s would be the better choice. I can use mine without a tripod although the tripod helps. Between the 12 and 15s, I use my 12x50s primarily but I like the 15x56 in the car.