I'm a trained machinist, so that's why I'd fiddle arround with these projects
The o-ring would do fine with a NBR-70 seal .. M10x1 for the studs, making my own probably ..
That copper thingy is 56x56 mm - no fins, cus .... it would be cheaper to produce, considered I don't have acces to a shop .. And it's just for a school project, so it'll do