Swinging away from the animalistic options.
Bracket or heads up. For the two day meetings (most of them) how about running bracket on one day and heads up the next? Sportsman tree for bracket and Pro Tree for heads up. Similar format to Top Sportsman. I am sure York can handle the different routines, they do it all day in any case with rwyb, HRG and Super Cup (Pro Tree), Sportsman/Pro/ASS (Sportsman tree).
Why do they have 2 different trees? To bracket race on a Pro tree would always give the slower car the advantage as to sit is stage for a few seconds waiting for the tree to run it is difficult to get a good reaction, whereas for the slower car they know pretty much when the tree will run, when both cars stage. Sportsman tree offers no advantage.