Hi Chris,
What a coincidence, I just finished baking two loaves of 'tater bread this
morning and then see your inquiry.
The addition of potato to your dough whether it be flakes or actual mashed
potatoes, will have the same effect. It will cause the dough to be much
more soft and supple. I've never had it turn into a "gloppy mess" but it
completely alters the feel and texture of the dough. It would be my
suggestion that you periodically remove the dough from the mixer and give
it a few kneads by hand to get a tactile feel as to how the gluten is
developing. As soon as it has the proper firm fell you want, quit
kneading. Also, when dough rises, the fermentation process that is taking
place causes further development of the gluten so don't be overly concerned
about under kneading your dough.
Chris, tater bread is definitely "Good Eats" so don't give up.
Happy Baking!!!
Don B