I've heard that too Dave. The 555 is fine as is and would be suitable for your applications. (knowing you). But they have removed their tobacco flavours from the site as we speak. They are offering a 10ml sample of stronger flavour for anyone making a purchase.
Time for someone else to take on for the team. RY4
BTW the RY4 did not mature into stronger as time went buy.
I did mix the 2 flavours at 60/40 RY4/555 (my daily vape) and all I get is 555 when using at 20%. It's not bad but not there neither. I am glad I only bought 12ml of ea. That being said, I can use the 555 in my own version of RY4.
I would haver liked RY4 to be on the money though. It is, just not concentrated enough.