Am I heading in the right direction?....

[JAZZCNC]

anyway, I'll take your advice regarding the brackets, positioning, and screws, - but this could change should I decide to invest in more expensive digital drivers?

You don't have to take my advice and by all means go for the larger screws etc but you will regret I guarantee you that.!!

Your doing the classic BIGGER IS BETTER approach and that's a sure fire way to waste money and build an under performing machine. Digital drives won't make any differance if they are sized wrong and mismatched to screws.
Even with the stuff I suggested I recommend you use Digital drives but this as nothing to do with giving more power but more to do with being smoother running and resonance handling capabiltys.