My first build had a $20 set of Akko CS switches and I swore they felt scratchy for a month before I lubed them. Turned out the scratch was my own bad filming job, not the switches, and they ended up smoother than the Zealios I bought after. Price tags mess with your head more than your fingers do.

My dad and me did a small slab for my mom's shed last fall, and we almost mixed it all by hand because he is old school and does not trust rentals. Rented a little 3.5 cubic foot mixer from the same place that rents out the party tents and it was the best $50 we spent. We got 22 bags done in an afternoon and the finish came out so smooth, no dry spots at all. Now I just keep a eye out for used ones on marketplace because a mixer pays for itself after like two pours. Your brother's slab holding up while the pit cracks is exactly how it goes, water gets in even when you mix with a machine and that is the whole game.