A short report along the way.
I have come to one of the final steps before being ready, and what do I find

One of the seats for the support fingers are out of angle

This means that the fingers does not meet nicely in the center as they should.
I think this is a result of my initial measuring out of the hole positions. I do not (yet) have a rotary table so I had to use a pair of dividers to step around the pitch circle. That went quite OK (I thought) but I forgot to check with a paper template made in the computer. It is very easy to make a triangle with a specific diameter and to cut it out to check. I did that now and realize that one of the three holes/seats are approximately 5 mm out of angle along the PCD.
So, now the misplaced hole is plugged with an epoxi-glued M7 piece of screw to allow a new hole to be drilled in the proper location. Following that, the seat will be re-milled to fit the support finger, and finally a small pad will be screwed and glued to fill up the distance towards the bottom of the seat.
Apart from this, the steady will work admirably! It fits like a glove on the bed and feels very ridgid. It has turned out exactly (well all right) as I anticipated and I think it will serve me well over time.
I did check the price again and it is around £16 at CES, see link below:
http://www.collegeengineering.co.uk/Castings/562.htmBR
/Peter