in my 30 years of recovery from knee dislocations and surgeries (too many to count), and horribly atrophied legs that were twigs at best to start, riding a bicycle has been the best way to get them back to even. I never worried about the L/R balance, but it always helps to check and make sure you are not favoring the "good" leg. That mental check, a few times a ride (esp. during the initial rehab period) is all I need to even things back out.

Not to say a new toy (PM that measures L/R balance) wouldn't be helpful in some amount, just that the miles and a little attention can go a long way.

I'm just recovering from PFJR surgery in april, with the longest rehab and most atrophy i've had in 20 years, so I feel your pain and wobbliness. Good Luck!