I do not stall rest and I certainly NEVER lunge or give forced exercise of any kind, how would YOU feel??
Unless there is a problem, in which case you go by your vets advice, of course, everything should go fine.
I geld when my boys are old enough, irrespective of time of year, so they are done while they are still on the mare, and they move when she does.
So long as you can ensure they are not standing around getting cold and wet he will be absolutely fine just turned out and allowed to exercise himself.
If you can leave him out 24/7 with a run in, all the better.
I agree about using straw, but then I never use anything else.
I have long, long since lost count of the number of colts I have had routinely gelded, I do know the first one cost me the equivalent of $2.00 and that included the Vets call out fee!!! LONG time ago, dinosaurs walking the earth
With every subsequent year and subsequent geldings I have made it simpler and simpler until now it is almost down to a fine art!
No hosing, no bathing (unless there is swelling) no messing around "up there" at all, apart from a twice daily, very quick (they are understandably touchy!) eye check to make sure all is well.
Expect a certain amount of "oozing," although there should not be too much, and expect a certain amount of swelling, but, again, use your head, and call the vet if you are worried, after all you can always send him a picture off your phone, these days!
I do give routine pain relief and I do use bute for this as it is the best, it is a good anti inflammatory and it is a quick pain reliever.
If you get the dose right you will give enough to take most hurt and leave enough to stop him careening around as if spring had come early!
Remember to keep him away form all females for at least six weeks, even if there is little danger of his being fertile, he can still hurt himself trying to prove he is still a man!
Good Luck, I am sure everything will go just fine.