Good grief! Ya' don't check in for a day and a half and you're 150+ posts behind.
@Nailz, menthol is an organic compound that can be synthesized, or extracted from plants. but the composition remains the same. To us, as DIYers; that means manufacturer shouldn't matter. The only two variants, that I have come across, are additions (e.g. menthol + extra flavors... such as mint), or concentration.
As for manufacturer's concentration... 10% seems to be the common concentration cut-off. Both menthol, and Koolada (a.k.a. WS-3), have a rather low saturation point in PG, and 10% seems to be about the max. If water, or ethanol are used, then higher saturation levels can be achieved. WS-23 has a higher saturation ceiling (~30%); and is why it is sometimes said to be "stronger" than menthol or koolada.
If your wife is looking to alleviate her menthol ciggie cravings; I would focus on just the menthol (and FW should be just fine), as both koolada and WS-23, do
not taste like menthol. They can offer a cooling effect, but don't have that Vicks VapoRub taste (some do get an artificial/chemical taste from koolada... but it isn't a menthol taste).
As for how much might be enough for your wife... this seems to be one of the more subjective flavors/enhancers. The majority of "casual" menthol users seem to find 0.5-2.0% (of the mfg's 10% solution) to be adequate. But, there are some menthol heads, who desire/require 10, 12, 15% (or more). So, it may take some wide-ranging experimentation, to find what suits her best.
On the "berry" side of things; I am a fan of the berry blends (forest fruit, mixed berry, berry blend) as the core note. All are easily bendable, to make one specific type of berry (black, blue, rasp, etc.), the featured highlight note... by the addition of whatever berry concentrates you might have on hand. Also, complimenting/contrasting fruit flavors, tend to mix well with these berry blends. Citruses, banana, peach, pear.... the list is long.
Final thought I had, while reading the above posts, is regarding stress management (the reason she is smoking the occasional cig?). If, the menthol vape route does not do the trick... and there are other mixes that work for her during non-stressful times; then consider mixing up a sample batch of one of her preferred vapes with a higher nic content. That may give her the extra "oomph" to get her through the stressful period without the need to light up. It has helped me in the past.
