Pulled my manual. Herpstat 2: Do not exceed 300 watts on either output. So I was wrong about the 300W total on the Herp 2. The Herpstat 1 says: Do not exceed 400 watts.
It's an EZ series user's manual, manual - HS012
I'm running 15 Herp 1's an 7 Herp 2's. An I'm still upgrading old stuff as it goes up. I like them just use your infrared thermometer to set an check temps.
Good luck!