I have seen many comments on the size of layouts. I have been reading a book my wife picked up at the library, and while it is devoted to N scale, (I run HO,) they seem to almost insist a layout should be at least shoulder high, if not eyelevel. I have considered 30", but that may not be high enough. I have a bad back, and bending over for any length of time is out of the question. Any suggestions?