Carbheat, try to remember that this is a contract position, you don't work directly for the airline, the contractor is 100% accurate when they say that upgrade is possible, but it won't be in any contract.
To date, pilots have moved from the ATR to the A320, 777 to A330, A320 to A330 and several from RH seat to LH seat and CA to TRI. Their is definitely no mention of this possibility in a contract from the agency because VAC allows this to take place only when it suits their needs on a case by case basis.
It is standard on this contract to pay your way to the screening, if you are successfully hired, you will be reimbursed by the agency you are working with.
Best of luck.