Wiring tips an aftermarket speedo/tach on an 84' Honda VT700 (Shadow)?

I have an 84 VT700 (Shadow). I initially was going to cut down the dash and run without a dash/speedo tach(bike came to me without one) at all, but I decided to buy a cheap chinese speedo that looked nice. On newer bikes this conversion would be easy, but i'm guessing because the original dash used non LEDs and the new speedo uses LEDs on the indicator lights, ther wiring doesn't match up so well.

Do I have to connect diodes between every dash indicator light (turn, oil pressure, neut., etc)? I have the colored wire that matches up fine with the wiring diagram in the speedo, but there is also what seems like a negative for every colored wire. Neutral light for example has a G/R but there is also a Br/B on the original wire diagram but there is nowhere to put the Br/B onto the new speedo. Do I need a diode between the two or how exactly do I wire it up? I would be glad to explain more if needed.

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