Good to see you decided to keep the model Jason.
Interesting choice of colors... building a new body too?
The 2x25... I don't have my old instruction for it... I'm looking at a 2x12 instruction sheet, don't remember if they're the same or not.
The four screw terminals for the rx, + - S1 S2 = wire both red into +, wire both black wires into -, and S1 plugs into Aux 1 ch (rx) & S2 into Aux 2 ch. I would use the red rx leads from both Sabertooths for BEC & delete the red lead from the Roxy. The Sabertooths seem to work erratic or not at all without the red leads going into the RX. Use of both red rx leads on Sabertooths to supply BEC, either one puts barely an amp, so there's no risk of injury there...
Dip switch 1 is down to turn mix off. Your Aux 1 & 2 tx 3pos switches will be operating each individually. Turn down EPA of each ch to 30 or 40% or adjust to whatever speed you're comfortable with.
You could use Dip Sw #1up (mix) so either Aux 1 or 2 is for/rev & the other steering as well. But slow EPA b/c @100% it's too fast!
I tried to use Aux 3 (dial) for proportional control of for/rev, but it doesn't work with the Sabertooth's mix without a lot of complicated programing manipulating sub trim & flight mode that's hard to explain & may vary from one model to the next.
There's a DX9 available now, it has sliders on the back of radio which would make use of the tracks a snap with the Sabertooth mix b/c both chs are full proportional control.
Dip sw 2 is down
Dip Sw 4 is down
Dip 5 & 6 the instructions will tell you the sequence to set your neutral center points & store them.
I tried the S20, I didn't like it b/c it had filtered hestitation from stop to start and minute movement back or forth when trying to maneuver my quick coupler into the receiver on the bucket was time consuming & often I would over swing b/c of the stalled movement for that approx. 1sec before activation.
I used the 2x12 for swing with Dip Sw1 down (mix off). The 2nd motor controller I use to operate my screener drum.
The instructions for the Roxy are pretty straight forward... probably best to use Aux 3 ch. I would assume dial turned all the way right is up & that's how you get into program mode when you turn on rx/model. Wait 3secs to set top - middle - bottom, then back to top & wait the next 8secs or so for the next set of beeps & go through the 5steps.
My 1st ever experience operating an excavator was a small Hitachi & the controls left stick boom/swing & right stick crowd/scoop... anybody I've seen who set their model up with Cat controls doesn't seem to operate their model very fluently... is it harder to learn or just bass ackwards all together, I don't know.
Just b/c you're painting it Cat, doesn't mean it has to be Cat controls.
Mixing valves with pump, all you really need to know is Master is the Valve ch & Slave is pump ch. Figure out which directional rotation is correct for the pump & get the + & - 100's in the right order.