Everyone has their favorite.
Stoner used a three prong FH originally, most of the prong versions seem to rate well in that regard. The Army bought 10,000 AAC Blackouts to use in A-stan, a prong design.
Constructor at ARP has a chart up rating designs he machines, the prong version all rate highly for less flash and better at redirecting noise forward. Short of a suppressor (sorry you can't,) it seems they are the way to go. Other designs that also seem to do well are the no hole/cut versions, like the Levang or Black River Tactical.
Anything with side ports horizontally or vertically will redirect noise back to the shooter. I'm being careful with words for a reason, FH/Comps do not increase or decrease noise, as the BATF then considers them a suppressor. Ask the guys marketing the .22 MP5 repro gun with the tube about that. We get to play with directing the perceived noise, not reducing it.
In MO a C&R, tax stamp, and cubic dollars will let you hunt with one, but for my budget, I'll wait for the Vltor Volks suppressor. In the meantime I've narrowed it down to an ITS 4 prong or BRT.
Not knocking the CNC investment, but what is it about all of them except the issue FH costing $50+? My Scots/Irish side gets all backed up about it. I'm thinking of literally taking a Dremel to an issue FH - but I ask myself, what little good does cuttting the web do except reduce the blowback marginally?
What the heck, I could try anyway.