9.5:1 on a small block with iron heads is pretty conservative. But a lot of it comes down to how tight the quench is, and how big the cam is. I can tell you that I ran an open chambered iron head at 12.2:1 and .030"~.035" quench on pump gas without issues. This was done by equalizing the chamber depth on each hole, and milling the block to put the pistons .070" out of the hole. VERY unconventional way of doing it. I'd be leery to mill .050" off the heads unless you were sure that the deck was nice and thick to start with.

How deep is the chamber right now on the quench side of your heads?

Honestly if the cam is big enough, the 10.1:1 will probably fly ok without detonating. Worst case scenario you knock a few degree's of timing out of it on the street, and put a splash of race gas and full timing at the track.

The best thing you could do is to buy a set of quench dome pistons and re-balance, but it's also your most expensive option so I can see why you might not want to.