Agree, crank up preload pre-install ... BUT ...
I would think about ditching that shock altogether and swap in one with remote preload adjustment ... common feature on modern shocks and a MUST for a travel bike. Worth it to upgrade if one will fit the Honda.

You're right, getting to preload collar rings is a PITA ... then having to bash your knuckles bloody trying to knock the rings round a few turns.

But good advice anyway, and if ride is then too stiff/harsh, it's easier to back off the collar than going tighter. Just be sure to UNLOAD rear wheel of weight, spray WD40 (or similar) on threads ... and be patient. You're in for lots of tiny hits to rotate the preload collars a few turns back.

More preload does not equal more damping.
What cranking preload up does is put you into a firmer range sooner, it may also raise ride height depending on Link design. But actual damping rates do not change ... but things will "feel" firmer, especially at low speed. (10 to 30 mph) This is often simple way to correct geometry by raising the rear end a bit, but does not affect actual damping rates.

To change damping you would adjust compression and rebound (bump) damping adjustments. (if that shock has them?) Both are separate circuits (on most shocks).

One thing to consider ... if shock spring rate is VERY stiff then it's possible the stiff spring will overwhelm the rebound (bump) damping, especially if bike is heavily loaded and ridden on very rough tracks at speed. But if the rebound circuit is quality and offers actual adjustment you can FEEL, then all will be right and will keep bike stable and prevent "Floating" at speed or after hitting a good bump.

Compression will affect the "feel" of the shock as it reacts to hitting bumps and also needs to be set to prevent frequent bottoming out. Bottoming out once in a while (on a SEVERE hit at speed) is NORMAL and it's what you want. (you should be using up ALL your travel for best performance overall ... but always best to be operating most of the time in the upper 30% of travel)

With too much compression damping your ride can be unnesessarily harsh. When it's right, you should have stability at speed and some plushness going over rough, rocky terrain at speed. Low speed may not be ideal.

Setting all this up requires fiddling and test riding on a variety of terrain with
normal load. It's very hard to get a bike to work perfectly at walking pace and at high speed as well. But with lots of fiddling you may get close. A quality shock makes a BIG difference ... and of course perfectly set up forks as well.

Forks are the "other half" of this equation and equally important. Balance between front and rear is key. Many end up chasing their tail on this. So tackle one at a time. ... then go chase your tail!