Remove the last 3 ingredients then just shoot for texture. for any given bottle, probably 75% chili, 10% vinegar, salt, sugar, garlic for the last 15%.
If you can match the consistency, you can probably match the flavor. You just need a line on fresh California Red Jalepenos.
I'd probably throw out the salt and just go for MSG.
xanthan gum is likely for texture, so why remove it then go for the texture after that? You can buy xanthan gum. I know it's also used in gluten free baking.
I think the magic is in the peppers and overall ingredient quality more so than the exact mixture. Given some trial and error in an afternoon with good ingredients, and I'm pretty sure you could figure this out. Hell, you can probably make even better :)
I have not tried this recipe yet as I have not been able to get my hands on a large quantity (for me) of good chilis, but I've had this bookmarked to play around with: