I am trying to find good info on the relative effectiveness on various designs of barrel porting on a handgun.    I have an extended barrel for one of my PSA Daggers (Gen 5 G17 in a G19 length slide), and a buddy with a machine shop, and having recently played around with a compensator on a different gun, I'm thinking it'd be cool (and free) to have my buddy cut some ports in the extended barrel and thus have a integrally ported gun (without cutting the slide).   He can cut basically anything I ask (holes, slots, longitudinal slots, horizontal slots, etc), but neither he nor I have any real idea what would be the most effective, so I'm looking for info on what would be better.  

Also, to be clear, I don't care about reducing recoil really, I am just looking to reduce muzzle flip.  

With all that in mind, would I be better to have a larger single port?   A smaller single port?  Smaller but multiple ports? Holes? Slots?     I would tend to think a larger port would release the most gas in an upwards direction (ie: release the most energy/reduce the muzzle flip the most), but it also seems logical to think that a somewhat smaller port (or ports) would create higher pressure jets of venting gas which might work better than a single larger port?

I see a lot of variations of this design with fairly large horizontal cuts, but is that because it's the best design, or because it's the easiest to cut and clean up any burs inside the barrel after cutting?:



Sometimes smaller width cuts, sometimes with the cuts angled forward (angling them forward would seem logically be less effective than having them angled straight up?)



And of course holes (most often on revolvers or on guns that have the slide cut-outs):



Also, there are the longitudinal ports like these (not sure why that would do any better than horizontal cut ports?):



Thanks in advance for any insight you can offer.

Guess I should have asked in GD - I bet 100 guys there would have already claimed to know everything there is to know about porting barrels, and started a fight with each other,  LOL...

Comps are better.
Just sayin'.
Ports that work include the Chunk Port and Lucky Sevens, but those require a cut slide.

Engineering Design Handbook: Guns Series, Muzzle Devices (1968)

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Loads fine for me.  Click "view full text of this report."  It's a pdf.