I've had the Stop & Go repair kit in my saddle bag for some time now. Have not used it on the Valkyrie --
knock on wood -- but have used it on the Shadow and other things. The success rate is around 20%. I purchased a cheap Slime string plug type kit earlier this year after the mushroom plugs failed (twice) on my riding lawnmower rear tire. So far, the string plug in the lawn mower has lasted six months.
Though pricey, I'm intrigued by the Nealey kit.
No tube of glue to go dry on you when you really need it! 