Is there enough thread engagement? Given the application and probable uncertainty about the material I would want to see at least 2xD.
Shimano QRs are still the best IMO, no need for the pricey ones, they’re normally long enough for most dropouts…
TBH I never found chain tugs bought much to the party when using QRs in horizontal dropouts.
One thing a few people used to do was tap the end of a hollow axle (M6 IIRC?) to a reasonable depth so they could use a hex bolt (and ideally a knurled face washer) on either end to secure the wheel, never bothered myself, but should work and you keep the option of going back to QR should you want to…