It's best NOT to have to rotate the piston at all during the install.
That said, it's pretty tough to 'guess' right when you use the 'piston-in-first' method (placing both the cylinder AND the piston together onto the cases/rod end).
No, you cannot see the ring ends once the piston is installed. Well, if you DO, something is very wrong!
You're likely OK, though. As already said, to force (and that's what it would take) a piston in that had a ring misplaced is going to take some effort. Once the piston is IN the cylinder correctly you don't have to worry much about the ring end going anywhere.
That of course is true only if you don't have to rotate that gap past a port. You would have to have the piston placed 'off' a good bit to have to do that.
It is considered generally good mechanicking to guide the rings 'through' the intake port when you slip the cylinder/piston on. Do that by sticking your fingers IN the intake port, putting some pressure on the rings as they go by.
If your piston indeed moves freely up and down with no binding, you're probably fine.