I haven't seen info of people mixing with Hansen for many years. They did some great tobaccos. I think I'll have to hunt some down now
I believe the sweet spot used to be around 5 to 8% for most of them around 2015 but that's when most ecigs were a bit crap so you'll likely be happy with the flavour mixed at lower percentages.
If I were you I'd do a couple of small samples mixed at 1% and 3% and see what you think of them fresh and then put them away for a week or 2 and sample them again. That should give you a good idea of the strength of flavour on newer kit. If I remember rightly they didn't seem to get stronger flavour with age. I could be wrong though.
I suspect the sweet spot for most of the Hangsen tobaccos will be around 3 to 5% these days but again, I could be wrong.
Maybe someone will come along who has some more recent experience with them.
Hmm, I'd start at 5%, I believe HS Essence is also Hangsen, they come recommended at 5 -15%, i used to use the RY3 a lot and it was superb. I wouldn't mix anywhere near 15% but then I've only ever used Hangsen concs in a blend, not standalone.