What my original plan was when i did mine, was to do all the measuring up one day and re-assemble. Then another day when i was free, do the swapping over. Its a bit of a pain to strip it twice but the work load is spread over a few days and your not in a rush to beat the bike shop closing and beating the daylight. In the end it was much quicker than i thought to do so did it in one day.
Only problem for me is im not attempting this on my own as I dont have the tools, my bike mechanic friend is coming over to help me / do it while I watch and I need to time having the car (which the missus uses for work) so I can pick him up as he doesnt drive. Its going to be a delicate operation