Which site has the toughest low limit SH games?

The vast majority of my experience playing online has been in full rings games, at which I'm a consitently winning player at $2/4 and $3/6.

I read up on short-handed play when I started hearing that the games at many sites were much softer in 6max than full ring.

I played almost all of the recent PokerStars reload bonus at 6max, and I've played a bit on Prima, Absolute, and the Crypto sites (most of this at $1/2).

I can say without a doubt that this 6max experience has made me a better full ring player. I'm much more aggressive heads-up than I used to be, and get far more out of my marginal hands.

However, I'm still not a winning player at 6max itself. I'm a consistently losing player (even if only slightly, according to Pokertracker).

I'd like to spend some time playing lots and lots of 6max, but obviously don't want to drain my bankroll doing it. I want to play against skilled competition so that my game can improve, but not have it cost me a lot.

Is there a site where the $.50/1 6max players are as skilled as the $1/2 and $2/4 ones elsewhere?

One where I could work off bonuses at that level would be even sweeter.

Thanks