The 4 slot extensions wouldn't stick so I printed 2x 2 hole extensions
yes, those 4 hole extenders gave me a bit of trouble too. I needed brims to make it stick properly. The print came out great! Thanks for sharing!
Yeah my Ender 3 would just give up after the 3rd hole and knock it over...despite 5mm brim.
Have received many compliments from the lab folks I work with, thanks for the design :)