I like Friday - less frantic than Saturday and more breathing room. You get to see and photograph without peeps constantly getting in the way. Still worthwhile IMO and I have been going for many years....
Saturday always has the largest attendance of any three day show. However, I seriously doubt you'll be dissappointed!
The vendor/exhibitor section should be just as good. The indoor miniature engine display is incredible...flat heads, Hemi's, Chevy v8's, etc. The car corral and swap meet will probably be at 75% or less on Friday. Still worth going to. I know alot of participants who will only show their car on Saturday and Sunday.
Fri is better than Sat, and you will have a lot less people walking around than Sat which is the busiest day. I always liked Fri as it was mostly the participants, more time to talk to the vendors and car owners. Sat morning was always hit the swap meet time first. Wish i was there instead of here in NM. Sun is the worst day with many people leaving to go home early. Fri will be a constant stream of new cars showing up all day as people get into town.