V-brake levers work ok with cantilevers, but the opposite isn't the case. Cantilever levers do not pull enough cable to operate side pull brakes effectively. There are some exceptions but for the most part... :cry:
Cantis are less eficient than Vs, so you need more power to brake on it. Levers for cantis are bigest than V lever. You can use V levers on canti brakes but you want more power at your forearm.