I just bought a set of Intiminators for my 2012+ DL650A. I've been thinking about what fork fluid to use with them. The 5w Amsoil without changing the rebound hole diameter, i.e., welding up the current and drilling a 1.5mm hole is not going to be as controlled as with the stock oil.
I'm thinking of going with Redline instead of Amsoil and am wondering if anyone else has tried it or similar?
AMSOIL Viscosity @40C = 15.7 with viscosity index = 210
Red Line Oil Light Weight Viscosity @40C = 18.4 with viscosity index = 407
( 5W yellow )
My experience is that Castrol and Motul 5W are a bit heavy for my 90kgs. They work, but there's a bit much damping. If anything, you may want to go a bit lighter.
There's no need at all to mess around with the existing dampers - what you do need to do is install them, put something near the recommended oil in, then RIDE the damned bike for a few weeks before you start playing.
The bike will feel different, it's unlikely to feel right *just because it feels different* and there's also some 'sticktion' until the Intiminators bed in.
I found that after a couple of weeks, and particularly the second weekend when I rode a steep winding road downhill, breaking extremely hard and extremely late into corners that whoever designed those things was better at suspension setup than I was.
Apart from needing to change the oil now and then and a little harshness (less than that caused by fitting K60 tyres) I found that they 'just work' (tm).
Obviously, your experience may be different, but I'd still say that messing around until you've ridden with them for a while (and in particular, you need to push the bike to near what it's previous limits were) is a total waste of time and effort.