Here's what I did to convert it:
Remove the black tube that has the weird connector on it from under the Blackstone. Put it in a vise and remove the factory connector that screwed to the regulator. Replace it with a male 3/8" compression to 1/4" NPT male adapter (Lowes sku 645791).Then add a double female 1/4" NPT connecter (Lowes # 645697)...you could also use a right angle here if you'd rather (I wanted to keep it straight to still use the regulator). Then a 1/4" NPT male to quick connect male. Don't forget to use propane tape or sealant and check for leaks.
The flow is still adjusted with the factory flow valve.
Let me know if you find a better way!
I also added adapters to the regulator so it connects to the quick connect now on the grill - so we are still able to use the regulator with cans in the backyard at home.