The smaller hi speed will delay the initial fuel down low and through the top end(richer) and a bigger hi speed will activate sooner (richer) and taper off up top (leaner). I had a scenario on my carb where it was stupid lean down low like 16-17 afr's and rich up top like in the 11's w/ .028's so I put .030's in and the curve teeter tottered rich down low and leaner up top just like that w/no other changes......EVERYTHING goes through the hi speed bleeds and they are active early in the run not just up top.............