Two overgrips makes the edges just a little bit hard to feel, if the base is synthetic grip instead of leather, but it's prefectly playable. Grip is a personal thing; I think I read in another thread where they had a test where people played with different sized grips regardless of their "normal" grip size and it didn't make much difference at all (at least for us tennis hacks).
When I first started tennis and bought my racket, I had no idea that I was supposed to use the "right" size handle. Got L4, stupidly put a thick cushioned replacement grip over the original cusioned grip, then put 2 more over grips. It was almost perfectly round.
Eventually my friend intervened and got me to rehab to an L3 + 1 over grip.
Just try 2 over grips and see if you like it.