Hey.

Do you know "REECE" were the oroginal MFG's of those things.

Then a bloke called "HAYMAN" an Australian.
Bought them out and markets them as H.R nowadays.

I still have a set of the originals.

The heads were fixed.
Not adjustable bolted like nowadays.

You set up, measured position of sliding unit.
Then welded it solid in place.

I Used 12 1\2 2.5mm Stainless rods to do mine.
Those V's were bottomless pits felt like.
I filled mine right up. With some inclusions.