For the attachment this is what I used:

Astromania Silver Plate for The Flash Shoe of DSLR Cameras - Mount The 1X40RD Reflex Red Green Dot Sight to DSLR Cameras https://www.amazon.com/dp/B06XYBR4P2/ref=cm_sw_r_cp_api_glt_fabc_HZRJECVTYNVZ9MP667T4

I liked the ability of sliding it on and off, never tightened it down. Even a little wobbly it helped me tremendously.