Oh experts, pray tell me how long for a boneless ham, about 5kg?
I'm guessing 60C for 12hours or so.
SInce its Xmas I will add apple juice and cloves...

I'm no expert, but I'd have thought a touch higher, maybe 63/65. (That's the sort of core peak temperature I shoot for when conventionally poaching an, admittedly rather smaller, bit of cured ham.)
Since you are cooking to equilibrium temperature and its not going to be "overcooked", I'd expect that longer wouldn't hurt - probably just render the collagen more thoroughly? Also, since he's likely a big lump compared to the size of your bath, he's going to chill the bath when he goes in, probably for some while.
Maybe worth remarking that the minimum time to attain equilibrium temperature is going to be determined by the starting temperature. The uplift from fridge temperature is half as much again as the uplift from room temperature.
There's one school of thought that the bone improves heat conduction - though I'm not sure whether this is due to the bone itself, the marrow or the bone/meat interface. Anyway, the result is that boneless would mean longer cooking.
My guess would be that 24 hours wouldn't hurt since you are going to equilibrium.
I think I'd be a bit cautious with cloves in the bag. I find them very pervasive in ordinary cooking, and suspect that
long sv might enhance that property!
Isn't it more usual to stud them into the fat after skinning and before glazing the thing? And for Christmas, wouldn't some Cinnamon, Allspice, Nutmeg, Ginger, Star Anise and even Peppers add some pleasant notes?
How would dry cider and/or bramley apple sauce do in the bag with or instead of the apple juice?
Are you going to put some onion, celery and/or other herbal aromatics in the bag?
Watching Nigella on BBCtv the other night, I was a bit astonished at the anise-heavy brew she came up with for her spiced ham poaching liquor. But the smoked paprika in the glaze sounded a nice touch ...
http://www.bbc.co.uk...ham_84672.shtml
"If you wish to make an apple pie from scratch ... you must first invent the universe." - Carl Sagan