The difference between a 220V and a 110V unit is in how the heater is wired.
If you have a 220V unit:
You can plug it into a 110V outlet and there will be no damage to the printer, however the heater will heat up much slower. For curing conductive ink, the bed might eventually get to temperature (we haven't confirmed it). However it likely will not reflow properly since certain ramp rates are expected.
If you have a 110V unit:
If you plug it into a 220V outlet, the heater will get immediately destroyed as soon as you start heating. There will be simply too much current. The heater will exceed it's maximum temperature, start smoking and become permanently disabled.
Please note, damaging the heater in this manner is not covered under warranty and we will not be able to repair the heater for free.
To answer your question:
In my experience the $20 dollar toaster ovens tend to be very loosely controlled and the temperature may swing violently. You might end up burning the FR4 entirely (we did that once...) so i'd advise to start with a low temperature and work your way up. The ink should cure at 200C for 30 mins. When baking, we set the temperature of the bed to 210C to compensate for the temperature lag between the heater and the board.
Your best bet (although more expensive) might be to get a transformer and just use the V-One as normal. This one might be a good contender. It has more than enough power (V-One requires 550W) and it's priced decently.