MP2 is 57/0 over a small sample
UTG is 78/22 over 30 hands

Kind of a weird spot here, not really sure what to do. I don't have any notes on their postflop tendencies so I just fired a smallish bet since its a pretty dry board

What better ways are there to play this hand? Thoughts on bet sizing?

Full Tilt No-Limit Hold'em, $0.50 BB (9 handed) - Full Tilt Converter Tool from FlopTurnRiver.com

saw flop

SB ($35.05)
Hero (BB) ($53.70)
UTG ($22.30)
UTG+1 ($61.30)
MP1 ($29.40)
MP2 ($19.85)
MP3 ($50.35)
CO ($50)
Button ($47.75)

Preflop: Hero is BB with J, J
1 fold, UTG+1 bets $1, 1 fold, MP2 calls $1, 3 folds, SB calls $0.75, Hero raises to $5, UTG+1 calls $4, MP2 calls $4, 1 fold

Flop: ($16) 7, 3, A (3 players)
Hero bets $6.80