milling heads for comp ratio increase

Like i said earlier, there is more to raising compression than raising compression.
With no other changes raising compression a full point and changing nothing else will net a modest gain both in horsepower and torque. This is fact. The amount of gain is debatable and influenced by several factors.
Where the bump in compression can really help is allowing other parts in the combination to be more effective, or allowing a bigger cam, as an example,to be used that could make more power because it might “like” the new compression ratio, and not like the old ratio.
Many things at work here, but bumping compression up in a lower compression motor is always going to be a positive step towards making more power. And milling heads is typically cheap. Cheaper than new pistons, etc. Just be aware after cutting the heads, you are kinda “ married” to them.
My own personal car benefited greatly from a bump in compression, just the throttle response and overally snappyness were notably different than they would have been had i just merely thrown the dual plane and mildly ported heads on it and otherwise left it alone. The extra compression allowed me to get away with a much more agressive camshaft it wouldnt otherwise have liked. Those modest changes resulted in a 10 mph difference at the track in the 1/4. And i say that as a veteran racer, who has raced forever.I made passes before and after. The compression bump was definately at the heart of those gains. Zero doubt about it.