On our Picnic Cat, the boom clears the Bimini with a few inches to spare. The Bimini does block some of the helm's view of the sail, but the shade is a welcome trade-off on hot days.
We've had only the tan cushions, but the dark green looks great. I don't think they would heat up too much on hot days, but can't speak from experience. Any color cushion beats sitting on hard, hot fiberglass, though.
Hope you enjoy the Picnic Cat. We're really happy with ours.--DW