Quest seems like it may be moot. Supply chain shortages for these items, as well as everything else in the recreation world.
My old 1.77" post system is being discontinued - not in the current Attwood catalog, although still available from others. Apparently with more modern safety testing standards, they are only rated "B", meaning only to be used if boat is going 5 mph or less (!). Many of the "238" posts are the same, but they do sell "AO" (Operator - captain seat) and "AN" (passenger only) rated posts and bases, some moveable. But good luck on finding them in stock anywhere. I found some in Australia - but shipping is a bit high!
Springfield and others only vaguely note, sometimes, what their systems are rated for (mostly "B").
The seats themselves are not so much an issue, but of course I want ones that match the old color scheme, which means custom work. Not ready to spend $250+ each for 4 for this old of a boat, considering the actual use it gets....so I'll stick with what I have.