does "not for fussy mechanics" mean it has the kind of fit & tolerance issues requiring some minor modification to the component (sanding, filing, etc) to install it?
I installed Leese crank a few days ago and the only annoyance i've had was getting the spacers combination right but that's just a "feature" of DUB cranks I think.
I used sram dub bb86 bottom bracket and i think the preload ring on the crank is too wide so you have to use a spacer on the non drive side just to avoid rubbing on the bb shell.
Sram suggests to only use 3mm spacer on the drive side but I ended up using 0.5mm on a non drive side and 2mm on the drive side. With 3mm total spacers it was a little too tight. Luckily Leese provides all kinds of spacers in the box.