What is best practice to create sheet metal during top-down design? When i start new sheet metal part in assembly on plane with in-place mate. Most of the time there are holes for pem fasteners and this is a point with problem.

If you want later move this part to sub assembly for creation component with those pem fasteners you are going to loose/suppress this in place mate or you have to use sheet metal without fasteners and just call on drawing for installing them but you will keep in-place mate. Second option gives me ability to to easier creation of drawing and sheetmetal flatness for waterjet/laser programming but lack of details in assembly view (calling just install pem near far may make mistake on my site or installer on floor).

What you use or what is your best way to go around it. I can not find best way to approach solving this issue?

I can not use tree house in design process since on beginning i dont know whole solution and cant plan accordingly.

As part of this issue is sheetmetal as assembly to show sheetmetal part with toolbox pem fasteners or sheetmetal part with pems inserted into it. Second way it is hard later to create flat view for waterjet programing.

Please bring to table your way to work with it.