fuel gauge query

I have a custom 2008 m50 that I have built up from a writeoff. there were no gauges when I got it and I like the clean uncluttered look. the speedo is now a digital pushbike speedo rated to 200 k and works well, but I now have no fuel gauge. I am aware that the standard gauge is a series of bars but would like to mount a simple needle type fuel gauge. auto sparkies have told me that they need to know the resistance of the standard gauge but the haynes manual doesnt tell me this. any help or advice on what gauge to get would be greatly appreciated.

Don't know if this helps but the official manual says when testing the resistance

5 blocks - less than 17 ohm
4 blocks - 22 - 28 ohm
3 blocks - 33 - 49 ohm
2 blocks - 54 - 69 ohm
1 block - 74 - 83 ohm
Flicker - More than 94 ohm

It also says that the float should show 4 - 10 ohm resistance at "Full" & 90 - 100 ohm at "Empty"

Don't know if your guy can work it out from that