In article ,
"Martin H. Eastburn" wrote:

Martin, its the sort of job you do in 10 minutes with basic hand
tools. (Which most hobbyists, like young apprentices, never learn to
use - they are in love with the power of big machines.) The ONLY skill
required is to be able to mark out accurately the ellipse of the
cutout (I said that as well, previously) - and even thats optional -
plumbers certainly don't do it. I would, because I learnt how to apply
basic geometry, engineering drawing and marking out at Trade School.

I likely will wind up doing some variant on that method, there is a lot
to be said for simple and cheap.

Free men own guns - www(dot)geocities(dot)com/CapitolHill/5357/