Depends on the bike. As mentioned above, most off-the-peg bikes come built and just require a pdi – pedals & bars on, check it's all tight, check the gears and brakes work, inflate tyres, put on shop floor. Some companies are better than others at supplying bikes like this, I've had ones that took 20 mins and ones that took an hour.
If it's a full custom build with a brand new frame and brand new boxed parts then at least half a day – firstly that sort of thing is likely to be the more expensive end of the market and secondly customers who ask for such things are usually quite picky about the set-up. Plus things like steerers, brake hoses etc need cutting to length, brakes need bleeding and setting up.
As for torque settings, it depends what I'm doing. Usually no, if I'm doing anything with suspension then yes.