when i was shooting competitively i always ran 1 1/8 oz right around the 1250fps mark for shoots, light modified choke for singles and modified for handicap and mod over light mod for doubles (always shot bottom barrel first).
for practice id load 1 oz loads, i never noticed a difference in recoil between the 1 1/8 and 1 oz loads(my reloads that is) unless i was shooting some factory loaded handicap shell that was going max dram.
the difference in pellet count between 1 oz and 1 1/8 oz is like a few dozen for singles this isnt really gonna bump your scores by much you may pick up an extra target or two but at 16 yds if youre off youre off. if youre looking to get better practice and boost your scores shoot 7/8 oz with the tightest choke you got then at a shoot or after a while shoot a heavier load with a wider choke.
if youre in the game for fun and to shoot more go with a 7/8 or 1 oz around 1150 or 1200 it will help stretch shot and powder but if youre in the game to go to ATA or PITA shoots and try to win money or buckles id run 1 1/8 loads at a minimum of 1200fps, most other shooters will so why handicap yourself intentionally by using a lighter load.
when i was coming up in the ATA world i asked this exact question to an older gent that became my shooting mentor and is a WA St ATA hall of fame memeber his answer was "we're in this game to win money, buckles and handicap yards why the hell would you want to handicap yourself by shooting lighter slower loads?"