The mainsail is, more or less, a self-tending sail. Set it before you tack, and then let it flop over during the tack by itself.
Steer the boat between your legs. It's awkward at first, but you'll get the hang of it with practice. A tiller tamer won't help you tack, but, after you come onto the new course, it'll help you hold that course.
If you can steer with the tiller between your legs, then that frees up both hands to haul in the jibsheet. Put two wraps on the lazy winch (I've found that 3 wraps often results in the jibsheet overriding itself) and pull in all the slack before starting the tack. While holding the lazy jibsheet in one hand, release the working jibsheet with the other hand, and pull in the lazy sheet as fast as you can. If you can steer the boat through a slightly wider arc than normal, it will increase the amount of time you have to handle the jibsheets.
After the tack is completed, you can put an extra wrap or two on the winch, if necessary, and trim the jib and mainsail.