Sanchi, I do not have the lenses I mentioned yet, but will soon within a month or two.
A good friend of mine is selling me his mint++ Apo Grandagon 45 and 65 Grandagon N lenses for $1,000 USD each.
$1,000 USD is also what you can expect to pay on Ebay for mint Schneider ultrawides lenses of the same focal lengths.
But of course, I trust my friend first and foremost cause I can inspect the lenses beforehand.
Also, thanks for the link to Silvestri and Linhof. It seems to suggest that for appx $800 USD they will take lens and mount focusing helical AND Silvetri bayonet. That could be worth while.