Instrument cluster swap-lights to gauges

[1967KaiserM715]

Hoping to get some help before I completely screw up. I have a 1986 GMC C30 wiring harness, both engine and cab side. It is going in a 1986 Chevy K30. Neither truck had gauges, only Idiot lights. plus the wiring harness on the K30 was completely hacked, not worth my time to rewire, especially since the C30 harness was complete and matched the engine I am installing.

Engine is a 292(4.8L) inline, with HEI, manual choke 2 barrel Holley.

On the C30 engine side harness, I removed the choke wiring, AIR and associated wiring(I did leave short sections of wire, all taped/heat shrinked to avoid shorts). I left the oil pressure, coolant temp, alternator and starter wiring.

In the cab, and the real issue, is converting the stock idiot light dash wiring to stock gauge wiring. As I have it now-number slot on plug, circuit number, wire color.

1,11, light green.......18,30,pink
2,8,grey..................17,-,-
3,31,tan..................16,237,yellow
4,35,dark green.........15,150,black
5,39,pink/black..........14,-,-
6,50,brown...............13,-,-
7,25,brown...............12,39,pink/black
8,33,tan/white..........11,15,dark blue
9,150,black..............10,14,light blue

and then how it needs to be wired, and colors as listed on wiring diagrams.

1,11, light green........18,30,pink
2,8,grey...................17,33,tan/white
3,150,black...............16,39,pink/black
4,39,pink/black..........15,931,dark blue
5,31,tan...................14,-,-
6,39,pink/black..........13,237,yellow
7,30,pink..................12,15,dark blue
8,150,black...............11,14,light blue
9,35,dark green.........10,150,black

I am pretty sure I don't need to worry about slot 15,931,dark blue as that should be the choke indicator. But according to the wiring diagram, #31 on the engine side is tan for oil pressure, but I don't think it is the same #31 on the cab side for idiot lights. Do I need to splice into the bulkhead connector to add this circuit? OR should I splice the engine side and move the oil pressure tan #31 to choke dark blue #931, which means I can use the cab side #31 tan as the oil pressure gauge wire.

and Brown #25 for idiot lights is not used-but what will be used for the volt meter? and I think I need to add a resistor to Brown #25 for proper alternator charge??

I think the rest is self explanatory I need to add 1 ground(150, black), slot 7, #30 pink can be spliced from slot 18, #30. and one extra splice to #39, Pink/black.