Pretty much all the reproductions shoot high. I think they are supposed to be sighted in for 50 or 75 yards, or something like that. Looks like the front sight on the adjustable sighted Uberti is not the same one as on standard models - looks like the only option is to maybe have a taller front sight custom made for it.
The cap problem is from the caps not being seated completely on the nipples. The CCI #10's and the RWS are a bit smaller diameter than the Remington caps or CCI#11's.
You can try to seat the caps a little better by pressing on them with a dowel or something to make sure they are completely seated on the nipples, or try the CCI #11 caps or Remington #10's.
The Treso nipples are sized for #11 caps, not sure if they will work any better than the stock ones if you are using CCI #10's.
Not sure which size Treso your revolver would need - you might have to measure the cone length of the stock nipples to find out which will work best with yours.
The Possibles Shop has the stock numbers listed by by the different cone lengths.