I can highly recommend the one sold on this SBO site. We had the deluxe w/ screens on our H26 and it was very robust. If I recall correctly, there was an option to order with the snaps pre-installed, so that matching snap studs could be put in the hatch coaming, or, if you already have snap studs in the fiberglass, the canvas was shipped with loosely bagged snaps to be put into the canvas to match the positions of the ones in the coaming.
Even in chilly weather, we found it handy to pull back a corner of the clear material and expose some or all of a screen to let out condensation from cooking, etc. The rear portion of the cover only came down as far as the level of the companionway slider, and would dump water on to the existing pin boards, or you can install a companionway cover as Dave mentioned, and even install snaps to fasten the two covers together if you wish.
Easy to set up and tear down... I highly recommend it.