The saliva is a real stinker to control. I wear a Scop patch, and it helps, but the saliva returns when I eat anything by mouth. My saliva problem is not only volume, but thick drool.
My non-techie technique is to rinse and rinse my mouth, then wipe my mouth out with paper towels. Then I get the toothbrush, and can actually "pull" out the thick saliva. Then I bite on folded up papertowel for a few minutes. The texture of the towel seems to shut it off.
Another thing that helps is the BiPap machine. As I can't seal my lips, it blows air into my mouth, and that takes care of the saliva until I eat or drink something again. Also, I find the BiPap very soothing, so a BiPap break helps relax me and gives me a little energy.
These are Rube Goldberg solutions, but anything that half-way works is ok with me.
Can't give any advice on the catheter. I'm sure some of our more knowledgeable members will come through.