Based on previous input from many, mixing components isn't in your best interest. As noted the alignment specs need to be verified through the range of motion. SpeedTech's frame and suspension geometry is most likely optimized for their arms and what looks like their AFX spindles on the car. A quick call to Blake would be my advice. If they don't mate up you shouldn't have any problem selling the Ride Tech arms for a moderate "learning experience" discount.
Your project looks nice!
