I've done a total of 5 of these SXK Boxer 20700 squonk dna 250c conversions for myself and friends. The bottom part of the select button needs to be be shaved, then it works just fine with a 250C.
To avoid installation headaches, it's also a good idea to carve out/ shave a little of the screen cradle (where it mates with the board's edges). You'll see when you take it apart. One side of the cradle edge can "crush off" the USB current sense amp and its input filter capacitor. They're a nightmare to reflow back onto the board if you do knock them off. If you run into anything or have a question feel free to PM me.
And thanks for the link......ordered 2.
I got the link from someone here, I looked back but could not find who to thank
Thanks for the warning about the screen cradle and offer for help via PM