3mm Lineloc (MLD trailstar) trouble using 2.35mm line

In heavy weather you might want to back it up with a tauntline or releasable hitch.

Yep. The LineLocs are designed for 3mm line and will slip at moderate loads with anything smaller. The only exception I've found is the green Nite Ize 2.4mm reflective cord, and that only works because the reflective tape woven into the sheath makes it kind of bumpy which also impedes the action of the lineloc. I would recommend you either use the yellow 3mm paracord supplied with the Trailstar, or tie a slippery half hitch under the Lineloc after each time you tighten them. Depending on what cord you use, the half hitch might still slip.

Like David said, you can back up the gizmo with a knot, but that almost defeats the purpose of using line-locks in the first place.

I can never decide, bypass the ease of re-adjustment from inside my shelter and use lighter line or carry the extra weight line required by the line-locs?

I would prefer to use the 1mm line that David (Oware) sells because of its gripyness and light weight, but it won't work in the 3mm line-locs.