I'm not the resident expert on this subject, but IMO, you should talk to a competent builder in your area if you are going to have someone else do the work. If you're doing it yourself, use a reputable shop, let them work with you to figure out what you're after, then do the build accordingly. If you let some folks here know what part of the country you're in I'm sure you'll get some recommendations on who to use...
IMO, just milling the heads/using gaskets to raise the compression is not the only result you are after. The SE103/110 heads are poorly designed regarding flow characteristics, which translates into how quickly the motor revs and one of the important factors in a good build. Total HP/TQ numbers are not the only thing, but how quickly it gets there. If you really want to do it up right, have the heads welded up and reshaped, or purchase a good pair of heads to go with the cams you want to use.
It's all about what you want for an end result...big numbers cost big money, and there is a correlation between the numbers and longevity of the engine, IMO. You start getting a basically stock bottom end/drive train over 130, and other things can have problems, IMO.