In your opinion, which commonly available tubes sound appropriate? I'm
particularly interested in hearing from hams that have built units with
similar DC supplies.

This is likely to be a long term project, with minimum amount of time to
work on it at a time, and likely extensive amounts of time to find
appropriate components at a reasonable cost (think beer budget and
champagne dreams)..
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If second hand tubes are not considered I suggest to have a look at the
Svetlana web site.
If valves can provide the wanted power at 29 MHz ,they certainly can do at
1.8 MHz.

If Eimac or similar tubes are available like the 3-500Z , 2 of those in
parallel are fine and so is a single 8877 or 3CX1500

Ref ARRL Handbook 1995 (and probably others) ,chapter 13

Good Luck with your project

Frank GM0CSZ / KN6WH