When your ear heals, find someone who owns a set of small doubles, maybe AL80s or LP72s, to let you take them for a dive. Even a pool dive would be very helpful. There's definitely an adjustment period in terms of trim and buoyancy control. If all you have is one reg set, either borrow a doubles reg set (two 1st stages, each with one 2nd stage) or for a pool dive on manifolded doubles, just use your set on the right post, leave the left post closed, and the isolator open. Just wait for the flames on that suggestion! Remember, this is just a pool dive to get used to the balance/trim of doubles.
Working the valves is easy, in fact way easier IMO than reaching the valve on a single tank. You do have to learn the system, keeping clear about which post controls what device, but actually manipulating the valves is no problem. I really think some people over dramatize the valve skills. Once you get into overhead and other potentially dangerous scenarios, all sorts of skills become more important and demanding.
Anyhow, that will introduce you into doubles without spending a fortune. You really should think about why you want to use them, though. I use mine in very shallow spring diving frequently, for the sole reason of practicing trim and buoyancy with them for future cave diving. In terms of increasing bottom time on OW, NDL dives, a larger single tank is probably a better option, certainly less expensive.
