Converting from A4 to US letter format
Run % pstops -pletter '0(0,-.75in)' [ a4file.ps [ letterfile.ps ]]
(works on Linus machines).
Printing Double-sided
Simple way, but doesn't always work: % pslpr -SDuplex=DuplexNoTumble
Alternatively, inserting
statusdict /setduplexmode known {statusdict begin true setduplexmode end} if
as the second line of a .ps file should do duplex printing on HP printers.