I tried M&P's RY4 concentrate with not much success. At 20% with 50/50 and steeping for a week, it was very weak to me. After 2 weeks, no change. I ended up mixing it 50% just to get close to the RY4 I bought from them. That being said, I'm no DIY expert and probably messed it up somehow. I will stick to the highly rated already mixed juices.
I had forgotten that Mom&Pop sell all their retail juices as DIY flavoring concentrates. For 10ml bottles that are formulated to be mixed at 20%, they're not cheap, but they are proprietary and hand-made rather than re-labeled off-the-shelf flavorings, so that's a big plus.
Yes, Texmac, something is clearly amiss with your RY4 misadventure. Never in my entire DIY history have I had a flavoring that could be mixed at 50%, at least not without the
juice tasting awful. (I've never actually risked a 50% mix, but I've done my share of ruining juices by over-flavoring.) I'm not implying that it's your fault---I wasn't there and have no way of assessing where the problem was. All we can say for sure is that, at the recommended 20% mix, your DIY RY4 should taste
exactly like Mom&Pop's retail RY4. If it doesn't, we know for sure that something's wrong somewhere.
To remind myself how they taste, I just vaped all
three of Mom&Pop's retail RYs. M&P
RY4v2 was and still is my favorite of the three. M&P
RY4 has the unmistakeable signature of Tobacco Absolute (TA is like an essential oil of tobacco dilutedin an alcohol base), and M&P RYO has the muddy, thick-tasting tobacco-ness that's characteristic of Tobacco Extract (TE is essentially TA made as a super-concentrated extract using PG rather than alcohol as a base carrier). That's not meant as a slam, by the way, but such a relatively blunt use of TE is something of an acquired taste. For hard-core NET fans, though, RYO is worth checking out. I like RYO a lot in small doses.
I've added all three of Mom&Pop's RY flavorings to The Big List's all-in-one RY4 pre-mixed DIY flavorings page for the next update.