Microshift thumbies incompatible with XT mech ?

Working on the modern today, but I'm stuck with the gearing.

Long ago I bought a set of Sun Microshift thumbies in 3x10 fashion, but I never actually used them. Currently I am trying to get them to work with my 3x10 Deore XT drivetrain. The rear one (first one I tried to set up) simply won't work properly. It won't engage either the top 2 gears or the lower 2 gears, depending on how I adjust the cable. It also doesn't fully engage the last gear it is willing to go to.

Basically I only get around 7.5 gears, despite clearly feeling a 10-speed index (9 distinctive clicks).
Friction mode doesn't help either, except that it allows better adjustment in the gears that were rattling and jumping in index mode.
All the parts are brand new, the cables have no friction whatsoever, the rear mech (XT M780 shadow) only has one option for cable routing.

Anyone have any ideas what I could do? I'm starting to think that there's a leverage issue which could mean that these shifters are for SRAM drivetrains.

Re: Sun Microshift levers incompatible with XT mech ?

are the travel limiting screws wound out on the mech? simple thing to over look.

Re:

Nah, I did think about that and wound them both out almost all the way.
Also, if that were the problem, it wouldn't explain why some of the gears simply won't engage and need a double shift.

It really feels like the shifter only pulls the cable about 75% of what the mech needs.

Re: Sun Microshift levers incompatible with XT mech ?

hmmmm seems strange thumbies are usually headache free.

IIRC The micro shift 10 speed uses the road pull, so needs either a 9 speed mtb mech, or a road mech (long cage)

Might be worth checking up along these lines.......

Re:

That turns out to be the problem indeed. No way I'm going to buy a new mech, I'll have to revert to the M770 shifters.

Bugger, I really wanted to use those thumbies to add a retro touch to the modern.