Some good hints about counterpoise types for vertical antennas… elevated vs. ground can be found here: https://consumer.steppir.com/radial-systems-for-elevated-and-ground-mounted-antennas-2-2-12_2018/
short summary… ground counterpoises with 0.1 lambda work well…
Works well for Sota. Tested with MP1 and HF-P1 antennas.So no need for 0.25 * lambda elevated radials…
73s
Ingo