I've got a 16" A3 flat top upper w/a front sight post and need options for mounting a scope.

What is the best one piece mount w/ 1" rings??  Will these allow a 10x scope to be high enough to clear the front sight or will the scope line up w/ the FS??

Will an ACOG and a TA51 mount clear the FS or be lined up with it??

scottMO  

The best mount for a regular scope is the Larue SPR.  It's pricy, though, at $195.  
You don't need a 10x scope to clear the FSB, you won't even see a hint of the front sight at 10x, even with the scope mounted low.  At about 3x, the FSB becomes invisible.  

Yankee Hill makes a riser/rail extender that's pretty cool, and dirt cheap at $35.  It'll allow you to move the scope forward for proper eye relief, and to clear a rear BUIS.  Same end result as the Larue, but cheaper.  I have this setup on a lighweight build I did.  I bought 2 of the thumb screws from YHM, and I can now switch between a Holosight and a scope on that rifle without too much trouble.  If I had the $$, though, I'd grab a Larue and be done with it, but that'll have to wait.  In the meantime, the YHM setup is doing what I need it to do.  

I've since ditched the very heavy QD rings in this setup, since they're redundant now.

Another option for scope mounting is to grab and ARMS #36 EX...it extends you flat top out about 6 more inches, giving you plenty of room to use any rings you want and still move the scope forward some.  They pop up in the EE from time to time...there might even be one in there now.  

I'm kind of partial to the Armalite 1 piece mount.  It's not very expensive, about $75 and it works for my purposes.  I've got a VXII 4-12x40 in mine and it's rock solid with good eye relief.  MJD