I've just got a comfy collar from Amazon for Dylan, I think some pet stores supply them now as well, there's no way he would be able to move around in the cage with a cone on (he has to have 6 weeks cage rest after his elbow op on Wednesday).
Also when my bridge girl Tessa had to wear a cone after her spay (there wasn't any other choice then) she was really depressed and they're really uncomfortable to lie down on and they keep banging into things, also it stopped any air flow to her ear canal.
The only advantage with them (for her) was she could scoop up any nasties that she rolled in

and save them for later!
I hope Jethro's op all goes well tomorrow.