I've just recommissioned a broken Bausch & Lomb Criterion 4000. It's
clear that I need a ground-based tripod. The books says:

"... a very sturdy tripod with adjustable panhead ... attach to the
tripod by virtue of the 1/4 x 20 threaded holes in the base plate
[there are three holes in a line, 6cm apart]."

The 'scope weighs 4.4 kilos. Its base plate is 17.8cm in diameter.

I find lots of tripods on eBay but most of them limit the attachment
weight to 3 kilos.

Any thoughts on what I might consider?

Thanks, Tom