I thought about this for quite a while earlier in the year as I needed a bike for a big trip around Europe. I felt my BLT2 with 140mm forks was a bit too steep (old Blur, not slacker carbon one) and was thinking about buying a second FS bike.
In the end I went for 160mm coil Lyrics with travel adjust and a set of off-set bearings to slacken things more. Worked a treat. I had thought I’d go back to shorter forks when I got home, but I havent bothered (and put then on a hard tail instead). I dont wind the forks down that often either.
170mm should be OK, might invalidate any potential warranty claim though. I’d go for 160mm in your position, plenty enough for anywhere I am going to ride.
I saw a carbon BLT recently with Fox 36s and a shorter stroke shock installed to slacken things, looked really good and apparently rides better all round than a Nomad. Was very jealous….