There are several choices for RY4D, so read the Notes on the ELR Home Flavor Search Resource Search tool and use the median% …8% sounds high, maybe 4-5%, but it would be different for those different Vendors because some may be stronger that others.
Like RY4 Double (TPA) [Scroll down and read “Notes” and look for the “Median %”]
Holy Holy Grail RY4 (DIYFS) [mentioned above] (Maybe 6-7%?)
Search for RY4 and see other Vendors. Realizing RY4D may not even be what you are enjoying in the Commercial vape. RY4 is one of the lightest tobacco flavors, but that’s why I like it personally …also I’ve never had the “Ruthless”
Also, no way this is a Shake n Vape. 2 weeks minimum 4 weeks better (especially if adding Creams/Custards) I’m vaping a little RY4D experiment myself right now with Creams, Graham Cracker, Nuts, and Cinnamon Crunch (Flavorah)
Vanilla Custard and Swirl might be too heavy …maybe Cream (Flavorah) 2-3% instead