Eric & Peter
I also ordered from Fastcap and put the 4" bristles over the Kapex shroud - used three 6-32 screws with nuts and washers with a hole punch to mount the bristles up as high as possible while leaving the shroud in place. It does create a more concave form. I did not heat the shroud or the bristles.
Will try it for a few days and see how it performs, but I can already see on a few cuts that it is less dust than I had with just the shroud.
One other thing to possibly try - you could pick up some brass stock from the hardware store - 1/2" x 12" is what is stocked locally - it comes in different thicknesses for stiffness at our local Ace Hardware stores in the state. You can then bend that around the shroud to further cup the bristles in place, and bolt it in place on the back side. That might help to hold the bristles tighter. I did find that mounting the bristles higher that they naturally were cupped more than at the bottom as you did with the 2" bristles.
I tried to order from the FOG member here who came up with the idea, but after two PM's to him, I never heard anything so not sure what is going on with him selling. Appreciate the idea from him none-the-less.
neil