New bike shoes 4 days from A race

I have a similar situation with my bike shoe vs. tri shoe. The biggest factor for me was the thickness of the bottom plate of the shoe. One shoe vs the other was 3-5mm different. Now I don't wear my cycling shoes on my tri bike. Anyway, that and if the backs of the shoes are similar then just stand them upright on their heel and visually adjust the cleat. The human eye can be a good as 1mm visually for something like this. If that doesn't satisfy, the measure (if the shoes are the same size ) from the front of the sole plate to the screw holes and if that is the same you can duplicate from there. Really, this will get you close enough with maybe a bit of tweaking on your rides.