BTW, now if you are interestinged in running two circuts in the same
cable, why have you ruled out 12/3 ?

I had it in my head that sharing a neutral for two circuits was a big no-no,
so I never considered that option....

Might want to post what you doing(or intend on doing) to get
suggestions how to do it best.

As it turns out, I found a better route through the house and have enlisted
a helper, so I'm going to KISS and run two 12/2 romex cables...

What we're doing:

Circuit #1 - 20A -
To support an electric hydronic baseboard heater, 750W. Also on the
circuit will be under tile electric warming mat at about 300W. A GFCI
breaker in the panel to protect any faults with the baseboard heater.

Circuit # 2 - 20A -
For general lighting and outlets in the bath. GFCI outlets of course.

I decided to run two circuits because I couldn't see one circuit handling
baseboard heater + tile warming mat + lights + fan + hot curling iron +
1500W hair dryer.... Sure I could probably get away with it until she kicks
the hair dryer into overdrive g...

-- Paul