I have a cooler that fits perfectly under the filler cushions down the center and when my son is with me, who is now 6', I slide the cooler in front off the helm seat and we stick the throw flotation cushion on it and it's perfectly level with the birth cushions. One of these days I'm going to get a custom made cushion and install a few snaps at the edge of the birth cushions to hold it. I put my feet in the corner behind the bench seat and sleep on the port side. I'm not sure if that was the answer you were looking for as you said that "the birth is very comfortable to sleep". Given your heights I thought you may be looking for more length which is a bit of a problem in the 21/2320's at about 6'0 and above. You can see the cooler in the pic