This is exactly what BJR was saying about cheaping the work load and value of the porter working on the heads. These parts are cheap at the meets. Seel these parts and roll it over into the bank roll savings for the porting work.
Yes. You should. I have several sets of heads to start practicing on. I also have 3 sets of heads waiting on a bank roll to have done. These are the heads I value over the junk heads and want for later builds.
(Notice how I will try my hand on some junk but will have a pro do work on what I want to keep and run.)
The above mentioned MP porting templates are for certain heads only. If you can find a set of 308 heads, theres templates for them. The only small block stock head that has templates. Then theres the W family theres porting templates for.
For a mild street engine, the above advice is good and you can gasket match the heads exhaust ports. The gain is small, but small steps is where you start.