If anything fails with the stopper during homing, the printhead might slam against the left side of the printer. The first thing that gets hit is the BL-touch, which is fragile. Now the wheel will be the first thing that gets hit against the left side. But still allowing for enough room for printing.

cap bolts screw nut:

https://www.amazon.com/Hilitchi-510pcs-Stainless-Socket-Assortment/dp/B073SW4S6C/ref=bmx_1/138-6368580-7083225?_encoding=UTF8&pd_rd_i=B073SW4S6C&pd_rd_r=11d0c6b2-58af-4b31-b899-d2d3ec2e06d4&pd_rd_w=qvqAT&pd_rd_wg=TsvxY&pf_rd_p=72f29bc1-c160-4012-b633-f54cb49b9557&pf_rd_r=KW8ZGAVYR7NZANKG09ZN&psc=1&refRID=KW8ZGAVYR7NZANKG09ZN

M4 screw is preferred.

have fun!