Model Railroading > NWSL Stanton drives for HO-scale diesel locomotives

Several years ago, I had a custom builder take my Athearn ALCO RS-3 (New York Central 8304) and my Bowser Baldwin RS-12 (New York Central 6226), remove the existing drives and trucks, and replace the trucks with NWSL Stanton drives and add DCC sound (Soundtraxx Tsunami), speakers and lights.
The ALCO RS-3 turned out reasonably well, ran well on my layout and had good sound.  The Baldwin RS-12 did not turn out well at all as I had only ordered one power truck and did not take into consideration the weight need the wheels from slipping.  Also, the frame would not align properly with the body shell.   Moreover, in both locomotives, the custom builder mounted the decoder and speakers on the body shell and not on the frame.
When NWSL was about to go out of business in the Summer of 2019, I ordered enough Stanton drives to take care of all my four axle diesels plus add a second Stanton drive to the Baldwin RS-12.  My first project will be an Alco Models Brass FM H-20-44 in New York Central colors.  I expect this model to be the easiest, as the current trucks are held to the frame with a center screw.  DCC, etc., will come later.  The next locomotive on my list is a Bachmann FM H-16-44.  This will be difficult because of the split-frame and the way the trucks are mounted.  Has anyone solved this problem? One possible route would be to start with one of the road-switcher frames from Rail Power Products.  Any other ideas?
 
John
 

Maybe NWSL has an answer. But a new frame is the most likely solution. I havent gotten to my split frame engines yet.