i think it just be too much foliage, cut those leaves in half!

it needs to grow under ground right now, not above, KEEP THAT SHIT HUMID. keep in mind with that big of a cutting it will need proportionate roots to accommodate.

I've seen HUGE clones rooted with great success before, but for how much a smaller clone can produce in the space provided i see it somewhat pointless, a smaller cutting (or two maybe) would probably fit in that finished space, so it may just be a hassle,

try it though.