Test pans from tailings to see what you're losing at 3/8 would drive me to make the decision about classifying smaller.
In theory, its always good to classify to bigger than the gold you're getting, but, How exactly would you change form 3/8 to smaller?
I'm picturing you using a 3/8 expanded metal welded or at least securely attached that will stand up to abuse. I looked into modifying one of my pieces of equipment to 1/4" punch plate, but that would have slowed down production and cost me about $200, which was not worth it for the dollars worth of gold I found. When I tried to do things cheaper with things like wire screen, the screen (chicken wire) would not hold up to abuse.
In my experience, classifying comes at a huge cost in time for me. I've dug 40 buckets of material by hand in a day, but by the time I got it down to 1/8", there was only 10 buckets left. That is done dry. Maybe wet is quicker.
As a guy who has spent a lot of money on bad purchases and poor home made mods, I would not spend anything more until after your Alabama trip. If you're tooled up, maybe you can even make the change at the camp.