It was a lot of fun, a great learning experience too!
I’m having issues with water channeling around the socks currently; despite a belveled friction fit pair of sock holes… I already have 1/2” thick acrylic rings cut to weld around the top of the filter sock holes so water has to pack up another 1/2”, then spill downwards into the socks, vs channeling around them…
If I did it again; I would just make a rectangular area which is recessed, with a perforated bottom in place of the filter sock holes; this would allow the use of filter floss instead, and make water forcibly flow down through it!
You do want to cut them loose! Cell cast acrylic swells up to 3% (more for extruded!) when submerged in water continuously… so compensate for this in your cuts; it should total around 1/4”, but check that math! — I’ve seen threads here showing tight cut DIY acrylic baffles actually tearing glass ranks apart at the seams, or completely breaking them!
the 20L sump under my hexagon tank only has a return pump weir with a bubble trap baffle; leaving a 20” open space to work in! — I used glass baffles for this, though! — cutting 3/16”-1/4” thick glass baffles 3/16” loose from the ID width of the tank left the ideal amount of space to inject silicone into the 3/32” gap on each vertical side of each baffle!
It turned into a full six week long project, including reinforcing a collapsing stand under a running 180g tank… it's a lot to read, despite me trying to keep it somewhat brief!
Hopefully this helps you in your materials choice, and final dimension planning!