Yep, as long as you have a large enough tub or whatever, the legs soaking overnight will be no problems.
Once again, try a rusty sacrificial leg first and get an idea of the outcome.

As far as i've experienced, there's no time limit for soaking, so if you forogt about legs soaking for 5 days they'll still be there, in tact and NOT eaten away ;-)   (well unless they're solid rust hehehehe)

I soak bicycle frames in plastic kiddy-swimming tubs (clam shells) and that works a treat.
I wish i was soaking smaller things like pin legs 

Marty.