204Ruger

I’m new to reloading for the .204 and was wondering if anyone had any Data for N133 with 39grn Blitzking, or would it be safe to go with what Vihtavuori have on their app for N133 and the 40grn vmax.

If you're new to the game, use the VV app data with confidence. Lots of N133 data about for the .223 (use it myself there), don't see much for the 204.

If you go over to Accurate Shooter forum and ask, you may get more/better feedback, but always use published data.

VV reloading data is trustworthy, however they do tend to be on high side, so start lower.
As for 133 in 204R, some have good results in the area of 26 grain with the 39 BK. Bill K