in case anyone's curious, i figured i'd run some quick numbers on presently available chain trigger combos in ngs. these aren't by any means thorough—i basically just ran a few fights against the cocoon bujin, avoiding crits and stylish roll strike back.
method one: charged point blank (full) + 4× stylish onslaught
(432 + 305) + 247 + 246 + 258 + 250 = 1738 damage
pp to execute: 20 + 4×10 = 60
this method is as in the video above. going by the numbers, allowing point blank to do both its hits seems to result in about 50 more damage than replacing the second hit with a stylish onslaught.
method two: charged bullet rave (full) + uncharged bullet rave (first volley only, four hits)
(85 + 78 + 81 + 83) + (74 + 78 + 85 + 81) + (38 + 37 + 34 + 33 + 33 + 33 + 36 +33) + 542 + (51 + 51 + 49 + 54) = 1669 damage
pp to execute: 2×22 = 44
it seems that even if you begin a photon art during chain finish, any hits that happen once chain finish ends do not receive the boost. it also appeared to be impossible to fit a stylish onslaught after a full bullet rave, which would have resulted in about 50 more damage than the above: possibly someone with less latency to the servers might have more success than i did.
method one (point blank + stylish onslaught) seems to do approximately 4% more damage than method two (2× bullet rave). if you were to successfully activate stylish roll strike back before chain finish, however, method two would gain the greater benefit and come out on top by about 4% instead (1962 damage vs 1885 damage). method two is also slightly less situational, since it can do its full damage from a moderate vertical distance, making it usable on certain bosses even when they are not downed.
a third method would have been to fire bullet rave without lock, and purposely whiff the first three volleys in order to trigger chain finish with the final hit. this would hypothetically allow 5 stylish onslaughts to be added onto the end, amounting to something like 1800 damage, but i'm not sure i'd be able to properly time it, and it'd be quite tricky to use; the whiffed damage would also result in more lost dps than you'd gain by successful execution.