Fitting a L39 hardtop is a bit complicated, because the roof design of the L39 is different (it extends the deckhouse roof whereas the L38 roof is higher than the deckhouse.
I think you could buy a L39 roof from R&C and mount it with custom made posts if you want to take this route
We fitted a simple plywood
frame (glassed over) with a large window. It rests of three small posts on the roof (can't go too high because of the boom) and the forward starboard post is a replacement for the original bar that was there.