Re: tube fly hook holder/ junction tubing
Don't know much about the tubing you mentioned. I tie a lot of tube flies for steelhead and buy the tubing on line specifically designed for tube flies. It's a bit more expensive but better quality & more resistant to cracking or splitting especially in cold water. I like HMH hybrid tubing, size medium, combined with HMH micro tubing. This stuff can be purchased at many online fly shops.
The hybrid tubing is notched & the micro tubing inserted into the hybrid tubing about 1/4" then lashed together with 6/0 tying thread. You can tie your fly on this hybrid, micro tubing with no need for junction tubing. Hooks I use are straight eye size 6 & 8 usually Daiichi 1650 or Tiemco 105. Fly is finished off with a size medium or small cone. Don't know what material the tubing is made of, believe it's silicone, not sure though. Google tying tube flies. Lots of info on tying them, patterns, etc. I tie mine on a tapered blind eye hook, Alec Jackson size 1/0, fits in any standard vise. You can buy different size tube needles to tie with. The blind eye hook works well for me & all I use to tie on. For what I tie, no need for needles or adaptors. Good luck with this. Lots of fun tying these.