I think
@GBBUDD mentioned using foam on rubber, then pressing moss into
Here are some of the mosses and how they do in full sun.
first photo is one of the best it is sitting on a flat rock where the water is just running over the rock. The moss gets 8 hrs min of sun and it has trippled in size this year alone . and the damn birds keep plucking at it looking for bugs under it.
second photo I have no clue but it to sees 4 hrs
Third photo
Irish moss it just touches the water but the main plant is raised and has about 4 hours sun
4th photo one I can find at the local nursery in zone 6 it gets 6 to 8 hours its irish moss it has white flowers and it is sitting above the water line on non woven that wicks water to its roots.
second to last is the bog that just got ripped apart a month back now and is still recovering everything was removed from the island to seam the liners from the addition " What we call dead pool and the pond.
The last photo shows some other moss that I have seen underwater in rain events and survive there for months its the stary shaped shoots and it to had doubled in size this year