I have started working on the sandbag strats with the USC's. There are 9 races with no known USC's. If I get 2nd place on 7 of those, then I can cut out a Ruff Trux bonus level, saving time (in theory at least.) Cue Ball Circuit is usually a safe one to get 1st place on, but it was a disaster, so I turned it into a sandbag. It worked out, and I had more flexibility later in the game.
Lost some time on Pencil Plateaux (15), Wide Awake War Zone (19) and Go For It (24) so I think a 33-minute run is definitely possible.
===RUN STATS===
Green: Anne, Spider, Emilio, Walter Red: Cherry, Bonnie, Joel Blue: Chen, Dwayne, Mike
2nd place on: Cue Ball Circuit (6), Bermuda Bathtub (8), Potted Passage (10), Bedroom Battlefield (13), Pitfall Pockets (14), Shrubbery Twist (17), Leafy Bends (22) [7 total]