We use fastflight plus here.
Here is an example of what we do on our personal bows here.
62" Field bow with hex5 limbs. 61lbs at 28.5" 12strand and it lasted about 8 months.
Now we think the problem with thinner strings is that it does bite into your glove/tab more... So when making your Thin string, add as many stands to the part that needs serving as needed to get back to your original happy size.
then serve. For example, if your working on an 18 strand string, and you want to run a 14 strand string, then add 4 strands into the serving section only. or even better, the contact area of your tab and nock, then serve and you have a light normal performing string withe the speed gains of a lighter one.
Now, our next concern about thin strings is the poor old nock tip.
If your shooting 16 strands, then that is what your bow can handle. Dont go cutting your tips off with cheese wire so to spreak, so do the same with the tips as you do with the serving, add some padding.
Now. With high performance weight reduction, there are warnings, the string is more prone to damage, so replace it more often... and have a back up. They do go pop! just make sure you replace it at regular intervals, and that way you can get more preformance without any draw backs other than needing a new string.
in short
you only need say 16 strands where the string is in contact with something. the rest can be less and the longevity is down to the number of strands you use...