Just to chime in, I have watched professional caulkers do their work before, and if it matters what it looks like at all, they do tape off each side of the joint. I would say though, professional caulkers don't use tubes of caulk, they generally seem to mix it and suck it into a caulk gun type thing, which more than likely is way cheaper than buying tubes. I would price things and get a bid and see what could be cheaper maybe. Not sure how big the gap is, but if it is say 1/2" wide, I would put the caulk in probably close to 1/2" deep, maybe 3/8" at the least (IMHO) I doubt it would go more than 5 feet per tube, probably more like 3... There are BIG tubes of caulk out there too, but you would need a big caulk gun.
Good luck
Steve