The Brits expended considerable ink and paper in search of the "optimal/perfect" gun. This is strange to me as they were, to my knowledge, first to put effort into making the stock fit the shooter; perfect fit. The arguments over what handling, feel, choke, barrel length, action type, point of aim vs point of impact, rib design, and several not worth mention, made "the optimal" gun. Aside from stock fit, there was scant consideration of physique, reflex speed, muscle speed, strength, and purpose.
I'd suggest you not worry about what makes perfect choke selection but, rather, what suits you. Shoot it as is for awhile before you make changes.
I'm shooting a Woodward BLE pigeon (only one Woodward made) after having it modified to my desires. Addition of a recoil pad took care of stock fit except I need more cast-off and will have that job done locally. The barrels were sleeved from 26" (30" OE) to 32", weight, teeter-totter balance, unmounted and mounted swing effort were to my specifications. Chokes were made mod right and full left so I could adjust them later. Loads for practice are 3/4 oz (21 gram - think 28 gauge). I am shooting it nearly as well as I'd expect for a true 28 gauge gun. I miss a few more skeet targets than with a open bore 12 gauge --- no big deal.
Shoot it awhile before cutting anything.