Sorry, Caledonian - got confused there.
Lolly! Make two lists: one of pluses and one of minuses, for both you and Lucan, and pin it on the fridge.
Add to them through the week and see how it looks by Friday.
If - outweighs + then reconsider. If not, let him go with the proviso that he can come back if things don't work out with his new mum.
Best to put his needs first.
You can always choose another more suitable companion for your resident cat, who will settle nicely, but this might be Lucan's one big chance to find happiness - you don't want to blow it for him.