Oh, OK... had me shook up there for a minute
I've done a lot of experimenting (and continue to do so) with combinations of "performance" CV parts and honestly, it's hard to beat OEM or something real close. I don't use a dyno just go by feel and plug reads and a drilled slide will work, but much better suited for either "on or off" throttle or a bar-hopper ride... if the bars are real close together.
Assuming you don't have a really tall cam, with a stock slide, needle (of about any size) and stock spring, a 175 may give you better mileage and will pull just as well. Problem with the drilled slide is that it raises more quickly as well as pulls higher with less vacuum. This causes you to have to run a bit richer than necessary just to overcome the imbalance of intake velocity between the slide and butterfly which is directly responsible for fuel input at the needle/main jet.
Ok, long story short - yes, get a stock slide and preferably a stock needle and jet holder (emulsion tube) and go from there.