try the different iron sets on rental weekend as mentioned ..
but i think the lvl32 R11 set is good to go untill the lvl59 G20 iron set .. from there i'd go to the lvl79 Burners or lvl83 G20's .. Burners are less forgiving & much faster than the lvl83 G20's, but they are longer, more accurate & stop much better on the green than the G20's .. Burners generally considered the 2nd best iron set next to the lvl90 R11's ..
possibly u'd might wanna consider the new RazorBlades which would likely be available in the mid-level ranges as MrWGT said they'd be more accessible lvl-wise when they are released .. i'd imagine they might be preferable over the lvl59 G20's .. just spitballin' on the RBlades since we don't know yet at which lvl(s) they will become available ..