B&M Heads-up play question

[Kirkrrr]

I ran into an interesting situation the other night playing at Commerce. Our 3/5 NL table got broken up, but me and one of the other guys decided to play HU. He's extremely LAG, so I figured it was only a matter of time. I had about 300 and had him covered.

We bumped the blinds up to 5/10 from 3/5 to make it more interesting. Here's the problem: the drop was still $1/hand, and about 20 minutes into it the floorman can by and sort of alerted us to the fact that we're dropping about $60/hr considering how fast we were playing.

So, Given: your skill level is higher than your opponent's and HU you can unstack him given time, could it possibly be profitable long-term at $1 drop per hand?

I'm very often in situations where the tables become extremely short handed late at night and normally I get very excited at the prospect, but that got me wondering if what I'm paying in rake kills my profit long-term. Somebody know the answer to this or a good way to figure it out? Assume 2/3 - 3/5 blinds and at least 100BB stacks.

All comments appreciated,
Kirk