Try our re-instated info resource - "Aladdin's Cave" (Main menu)- sorry it's taken so long to fix
Don’t worry I am going to buy some new coils from DS , it’s not really worth the effort to try and refurbish a set of coils.
Not wanting to sound defeatist here Ken but just because it comes from DS doesn't mean it's perfect for your requirements. Lots of reports on the forum of DS stuff being either wrong or poor quality. Your initial idea was a much better one IMO, the original Honda coils are almost bullet proof, the Achilles heel being the leads of course. The Ash fix cures that problem and should be good for many years and then can be done again if it ever needs it. Perfect fit, correct connectors etc. Ok it's more work but it's cheaper and better in the end. Plus if your a bit odd like me you can substitute the leads for another colour. My CB1300 has red leads for instance and I much prefer the look of those so I've done a set of 500/550 coils with red leads, along with a red silicon outer sheath like the OE leads and the numbers on the leads. The old numbers slide off the old leads with a little care so can be reused.
Try the green spark plug company. Used them a lot and always found they sell decent stuff.Little tip. If buying plugs consider buying ND plugs instead of NGK. Lots of reports of fake NGK plugs but none of ND plugs. Honda used both makes back in the day and there wasn’t much between them to be honest.Yellow leads? Yeah why not. I did have some spare coils for the 500/550 but without looking I couldn’t say for certain if they are the same as the 400 coils.