Tom,
I didn't have a problem with my spit, but I did have Tomo.
Hopefully there is someone on the forum who has had Tomo and also had your spit problem.
If not you might want to discuss this with your RO and the Tomo Tech since Tomo can take a bit more time.

After the tech did my initial laser/manual mask and bed alignment, It took about four minutes in the donut for the CT phase, then I came out of the donut for about five minutes while the computer crunched the numbers.

Then it took a few minutes for the Tomo to re-align the bed, and the tech to double check everything and leave the room.

Then I was back in the donut for about ten minutes. There seemed to be a tilt after about six minute that it seemed to have problems with and some days it seemed to take it a few tries to get it right.

The collimator on the Tomo is noisy - reminded me of Darth Vader - but it is the best.

If Tomo time is tight at you CCC and you have boost your last week to just a few areas, they might run the boost on a standard IMRT, or if they have the newer technology on a single-arc system (less that two minutes on a Varian Rapid-Arc system).