So WERA has been doing it this way for years with very good success. They do have some novice only classes but many are run with the expert grids.
here is what a daily race schedule from WERA looks like

http://www.wera.com/pdfs/2008Schedul...ings090609.pdf

9:00am - 11:30am Practice Groups as follows:
1) 600cc Experts 4) Lightweight Novices and Experts
2) 750cc and Up Novices 5) 600cc Novices
3) 750cc and Up Experts 6) Minis
11:30am - 12:30pm Lunch Break
11:40am Riders Meeting - Tech
12:10pm Chapel Service - TBA
12:30pm Pirelli/WERA Sportsman Series Races - 8 Laps each
1a) Minis - 6 laps
1) A Superstock Ex & Nv
2) WSS, HWT SB, V6 HW, V7MW
3) C Superstock Expert
4) C Superstock Novice
5) Formula 2 Ex & Nv
6) Senior Superbike Ex & Nv
7) B Superstock Expert
8) B Superstock Novice
9) C Superbike Ex, HWT SS Ex & Nv
10) C Superbike Novice
11) 125cc GP, Clubman
12) Formula 1 Expert & Novice
13) LWT SS, DSB, ESS Ex & Nv
14) B Superbike Expert, V7 HW
15) B Superbike Novice
16) LWT SB, DSS
17) A Superbike Expert & Novice
- Awards Presentation in Tech following last