The hot wires cables from Nology are supposed to be a great upgrade, but the boots don't seal well for all models, so if you are considering these, you may want to get on a forum and see if others have had issues with fitment. The hot wires that I bought for my Steamer also need to be grounded at the coil end, and I'll bet the Bonnie ones are similar, so you may also need to have a solid grounding location within reach of the coil end of the cable.
Lastly, even though you don't have a fuel issue, I'll mention two products that have eliminated all of the fuel issues that I used to encounter. The first is Star Tron fuel additive, which cleans your fuel system and also prevents the ethanol from separating in the tank and causing rust and corrosion. I store both of my bikes with a full tank of non-ethanol gas (when I can find it), and a bottle of the Star Tron. During the summer, I add a splash every other tank or so. Really great stuff, and has worked better at stabilizing for me than the Stabil marine that I used to use. It also has done a better job than the old standard Seafoam for cleaning fuel systems on some of my other engines. Really good stuff.
The other great product if you do have rust started in your fuel tank is the Caswell sealer kit. This is a clear epoxy based product that does not require any acid scouring prior to use. It is easy to use, and I have written a step by step review which is on webBikeWorld if anyone is looking at fuel tank sealers.
Since doing the Caswell and using the Star Tron, I have had no more fuel issues at all, and the bikes start each spring within about 15 seconds of cranking.
Good luck with your Bonnie. I think those and the Thruxtons are really beautiful classic looking bikes (even if they are missing one cylinder

