Boy, that seems like a lot of extra work, maybe if you are concerned with conserving milkweed leaves, I would think you might want to remove the egg from the leaf, since it is not going to be eaten for a few days. If the egg is kept on the leaf, and the leaf is kept moist, the little critter can start eating right away! Cut out the middle man, so to speak! I just started this hobby myself ( collecting eggs, that is) I like to put 2-3 leaves on wet paper towells in a ziplock bag, wait till they hatch, then transfer the tiny cats (still on the original leaf) to a bigger container, often with several others that just hatched, still on their original "leaf". This container has a tulle top, held on with a rubberband. When they get big enough, they then get transferred to a bigger cage, with a permanent top to pupate on. This to me seems to be working...
Monarch Waystation # 1,000