one piece?
have fun!
other input?
soft shoes and hydration are great ideas.
locate the bathrooms early on.
pace.
have a lengthy list of songs for audition as said.
see the major rooms or largest demos on the first day, VAC, MBL, . etc.
see as many rooms/demos as is possible thereafter and on Sat.
check out your preff list for gear on Sunday, arriving early well rested and fed.
bring with some music in various formats on the occassion you are allowed to use it/them.
there are likely gonna be too many demos to see them all. see as many as you can stand to see as there will be those which were maybe not on your radar which might be quite compelling.