Your rims look like a fairly deep V, you might need the extra length. Only way to tell is to stuff the broken tube valve in the hole and see how far you can get it to poke out. If it looks like you can afford to lose 14mm, then yes, but if you can find 46 I'd do that. Or, if you're mail ordering, maybe just buy a set of "presta savers" and stay with your prestas. I think it's easier to find presta's with long valves.