To gain about a full point of compression my slightly milling the heads is likely the cheapest hp you can get. Only reason for a dish is to lower the compression.

If getting it over 10.5:1 is very important to your and your builder, the easy solutions are either mill the heads, replace the heads with smaller chambers + get some that flow better at the same time, or use custom pistons with less dish.

The last option is going to be the most expensive, the first option is the least expensive, the middle option....if you sell your existing parts like bsb suggests, will probably get you the biggest overall gain for the money spent.