I brought this up in years past also. Its back now at Rocky Mountain ATV.
The "Myers 90° Tubeless Chrome Valve Stems" have been brought up several times (they have also been sold at the old Jake Wilson, now Rocky Mountain ATV). The nice thing about them is you can tighten after install as the adjustment is on the outside. They are only $2.
Free shipping at Rocky Mountain ATV through 12/19 with no minimum purchase amount, not the usual $7 minimum fee.
For $4 you could do the Valkyrie, or just have some spares on hand for the next tire change.
These could make great stocking stuffers or just buy yourself something.
https://www.rockymountainatvmc.com/tires-and-wheels/myers-90%C2%B0-tubeless-chrome-valve-stem-p