Hi all, planning my second chiner build, first MTB.

Am looking at the FM10 frame from TanTan: https://www.aliexpress.com/item/4000405521351.html?spm=a2g0o.productlist.0.0.68006c85XBdhkL&algo_pvid=1129719f-8eae-4e90-8630-3e3ab89d33c0&algo_expid=1129719f-8eae-4e90-8630-3e3ab89d33c0-18&btsid=0ab50f6215911011239063755ec180&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

With 27.5 wheels.

I have a question about sizing. I'm 5'9 with an 33.5" inseam. I'm not sure what size to go for.

I'm new to the sport, and think I'd prefer a more relaxed position, with the option to get aggressive. I'd prefer a short stem on the bike.

I tried a few bikes out in a store yesterday and was very comfortable on a Norco Sight (29er) and Jamis Dakar (27.5) in Large. The reach of those bikes are 485mm and 463mm respectively. Which makes me lean towards the 19" FM10 with 460mm reach.

Sight Geometry: https://www.norco.com/bikes/2020/mountain/all-mountain/sight/sight-c3/
Dakar Geometry: https://www.jamisbikes.com/usa/dakar-a2.html

What do you think? I'd appreciate any help you can provide.