Stacking stepper drivers for big steppers?

Hello.
Tomorrow I will be purchasing 1 or 2 Nema 23 stepper motors to upgrade my 3d printer. I plan to eventually use it for some CNC applications so the small Nema 17's I am using now probably will not be sufficient. I plan to continue using my Ramps setup for now and would like to avoid buying a couple of the larger Toshiba drivers. The motor's draw 2.5a according the site, up from 1.8 for the motors I am using now. I figure I can probably get away with using my current DRV8825's. I keep them at a VRef of 0.7v, so if I adjust that to 1.25v it should have enough power. But, in case I need a little more current than one driver can put out I stacked 2 on top of each other. I am using my A4988's for this test. I tested them, outside of my 3d printer, and everything fucntions normally. I am not sure exactly how I will set the VRef for dual drivers but in theory this double driver should be able to handle close to double the current, correct? Has anyone ever tried this or know of anyone who has, or has any possible warnings of some issues I may face.

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i would get some higher current drivers problems i see one driver output not synced with the other power from one output feeding back into other On the nema 23 use a higher vmot 12 to 24 heatsink bottom drv8825 were it was meant but then you would need to mount them off ramps board and run jumpers next question i ask what upgrade needs nema 23 ?? one metre bed the drv8825 will shut off if it gets too hot try one with the new motors final question u a member of reprap forum try posting there

@Draytology, I can't make sense of your Original Post.

Are you asking if you can use one stepper motor driver to control 2 motors? I don't believe you can - I don't see how the current in the two motors could be evenly shared.

You could send the same step and direction signals to two different drivers.

Or are you asking if you can pair two drivers to power one motor with a large current draw? If so I reckon one or other will see a too-large current and shut down immediately followed by the other one shutting down.

...R

Draytology:
But, in case I need a little more current than one driver can put out I stacked 2 on top of each other.

Absolutely not, they cannot be stacked, they will blow each other up if you try this.