Induced the squeeze, now what?

Opener was very loose, wasn't folding ever to 3bets. The BB had an uber high squeeze. What should my 4bet sizing be when in position here?

IPoker No-Limit Hold'em, €0.20 BB (6 handed) - IPoker Converter Tool from http://poker-tools.flopturnriver.com/Hand-Converter.php

MP (€29.67) VPIP: 25, PFR: 21, 3B: 14, AF: 2.2, 200 hands
CO (€11.20)
Hero (Button) (€20.78)
SB (€30.52)
BB (€21.20) VPIP: 23, PFR: 19, 3B: 4, AF: 2.8 Squeeze 6.9% total, 18.2% from BB (has only ever squeezed from the BB), 300 hands
UTG (€21.03)

Preflop: Hero is Button with Qhttp://www.flopturnriver.com/pokerfo...lies/heart.gif, Qhttp://www.flopturnriver.com/pokerfo...es/diamond.gif
1 fold, MP raises €0.70, 1 fold, Hero calls €0.70, 1 fold, BB raises €2.40, MP calls €1.90, Hero raises to ?

6.75

If MP wasn't ever folding to 3b I think it would be better just to 3b yourself. That and BB's overall 3b is pretty low.
But as played, I'd make it 6

3b pre is probably better here given that the fish is always calling your 3b and bb isn't going to oblige as often as you think
as played $5.40-ish