1958 GMC Carpenter CorsAir Bus-RV Air Brake upgrade needed

[wordlarry]

I need "knowledge" on how to upgrade my 1-Circuit air brake system (1 air gauge on dash, 4 “service only” brake chambers on front & rear (single) axle, etc.).
My Goal w/ upgrade:
(1) set up Emergency braking by upgrading to a 2-Circuit Air Brake System, complete w/ 2nd dash gauge, low air warning, PP1 Valve, etc. &
(2) creating Spring Brake parking via PP1 valve on dash and new 30-30 Serv. & Spring Air Chamber (Cans) on rear which I understand I can do as “direct bolt up”……
- Issue is what air value(s) (R12 or R14 or “Spring Brake Air Value / Relay Valve) valve would new 2-Circle (2 air gauges on dash) system need?

Currently I have two air tanks: (a) Wet (closest to Air Comp.) & (b) Dry tank

#1….Other than new 2-Circuit Treadle Valve, 2nd air gauge on dash, two upgraded 30-30 Air Chambers on rear, etc. & what Air Relay valves would be needed to plumbing all this new stuff up?

no air, Spring Brakes “on”/stopped = emergy braking; if working, PP1 on dash B4 driving away…..

Any (Carpenter - CorsAir) bus owners out there that can advise me .... I wanna do this "right" but EZ as well; no need to re-invent the wheel or make my old bus "modern", just safe is the goal....

MANY THANKS IN ADVANCE.....Larry