IIRC, Girl Germs, you're still in the early part of the trade. Not that there's anything wrong with that! Indeed, I'm delighted that you're sticking with it.
There's a line that is crossed when you go from running a convenience circuit to running a circuit for a known load. Since a range is a known load, it gets its' own circuit.
"Convenience circuits" are one of the stranger things in the trade. Everwhere else, we size the breakers and wire to the load; in a convenience circuit, you're quite likely to find a 1/4-amp alarm clock 'protected' by a 20 amp breaker. Nowhere else do we allow this to happen.
For more than one range, you're allowed to factor in 'deamnd' in selecting the wire and 'main' breaker size. Still, you need overcurrent protection on the feed to each range. As I see it - and Canadian Code may differ on this point - you can provide that protection either with a subpanel, or with a fused disconnect at each range. (The Square D "QO 200 TR" HVAC disconnect would do this, using a standard QO breaker).
