I'm probably not the best person to answer this, but I feel like trying to store them for any great length of time would decrease the viability or increase the chances of mold with the remaining leaves...
Esp. considering that it took a few weeks for mine to show the first signs of roots.
I was a little uncertain about the best way to root them so I tried about 4 different substrates in various locations (outdoor greenhouse, window sill, and terrarium). I had quite a few leaves to play around with. so I wanted to try to find out what worked best and not risk them all in one spot
Here are the substrates that I used
100% Perlite
50% Perlite, 50% Vermiculite
100% Pine Bark
33% Pine Bark, 33% Potting Soil, 33% coco coir
They all worked, but it seems like there was a higher instance of rot with the mixture of bark, soil, and coir. Maybe because it held too much water, or it may just seem that way because I had smaller leaf pieces in those pots. and of the leaves that I cut into 4 pieces, rot was more of a problem.
Whole leaves, whole leaves folded back and forth, or 1/2 leaves seemed to do better than the smaller pieces.
Of the 4 substrates that I tried, I was most impressed with the straight pine bark and the mix of perlite/verm. 100% perlite did pretty good as well but it may have just been the location that made the mix stand out. The only place that I had the mix of perlite/verm was in the terrarium at a constant 86F and near 100% humidity, while the 100% perlite was on a window sill inside a tupperware container.
Obviously there's not much in the way of nutrients in the straight pine bark, perlite, or mix of perlite/verm and I haven't quite figured out my plan to move them to soil yet. Just this morning I picked one with good root grown from the perlite/verm and transferred it to a mix of pine bark, coir, and soil as a test. If it takes the move well, I'll probably migrate the rest that way.