Just want to reassure people doing research for LC pedals that own a Playseat Challenge that these pedals will absolutely work. The velcro strap that comes with the seat to hold the pedals is all I use. I did, however, superglue a piece of the fuzzy bit of velcro onto the blank space of the strap. It has held up to about 4ish hours of racing today and is comfortably holding them up with the seat folded.
For reference, my spring combination is White-no washers-Red. I like the light preload and the hard resistance as it helps to prevent lockups for me. I find it really helpful for driving without ABS. Considering what the Playseat Challenge is, under hard braking, I can feel the chair flexing but not to a degree I'm concerned about. With my TX rumbling the frame of the chair and the creak of the Alcantara seat, it makes for a really immersive experience!
As for getting comfortable with them and the LC it only took about an hour. I went through a couple of setups (standard medium, Black-no washers-Red) until I found the combination that works best for me. The calibration tool is great and as was mentioned near the beginning of this thread needs to be set before you drive. For brake pressure, I press on the pedal as hard as I feel I will in a race then slide the adjuster until the bar flickers 98-100%. I found it again allows me to prevent lock-ups but it still happens.
I believe they are still in stock on Amazon and ordered them Thursday and received them Saturday. I finished the AC Club GT3 race about an hour ago and am completely satisfied with my purchase! I am more consistent and have a lot more fun rather than being frustrated due to inconsistent acceleration and braking. The T-LCM pedal set makes me
want to drive rather than it being a chore. Also, I set a new personal best of 1:33.2 at the Red Bull Ring today!