I'm not a huge fan of supporting Amazon but I'll admit, I use these and it does the trick. got them in a few days. Can verify that it holds the NH/7s movements. https://www.amazon.com/SE-JT64040-Watch-Movement-Holder/dp/B005URKHY2/ref=sr_1_1?dchild=1&keywords=movement+holder&qid=1588825175&sr=8-1
EDIT: that said, I support what u/seikosandrollies posted.