I’m glad Wayne already said this, I am just repeating so it doesn’t get missed.
You do NOT want a petcock with a reserve function. Fine for carb bikes where fuel starvation just makes the motor stumble and you turn on reserve before it stalls. Not OK for injected bikes. First of all, the fuel pump will burn itself up without fuel flowing through it. Secondly, even if the pump wasn’t designed that way, injectors either have enough pressure to work or they don’t. So the engine would just die without enough warning to switch to reserve.
Another option that nobody has mentioned is to switch to get a later model fuel tank with the pump inside. Bigger project, but doable.