It took me longer to strip off all the plastics, tank, radiator (I couldn't fit my hands in with it just rotated), etc. than to do the actual job.
The actual job is 4 bolts to remove the covers and a little work with a feeler gauge. If something's out of spec, then obviously it's a little more involved. Add a strong magnet to your tool list for the job, too. It will make it very easy to pull the buckets and shims out if you need to.
The time is getting it to the point where you can do that, and then putting it all back together. If you've done a lot of your own wrenching and can strip everything down quickly, and if everything is in spec, I think 4 hours is a reasonable estimate.
If you've never had your tank and plastics off, and if you need to pull camshafts, a day might be pushing it.
DISCLAIMER: I did mine, but I ride a Vee. I don't know if there are significant differences between the two (besides the chain vs. gear-driven camshafts). It was the first time I stripped my bike down, and it took a full day +.