A few questions about the white spacer mod.

I see that most on here went with a thinner spacer as opposed to removing the spacer completely.  Logic tells me that when the white spacer is thinned or removed the result is the needle sits lower into the main jet, therefore adding more restriction to gas flow through the main jet.  Doesn't this result in leaning it out in out at the top end? Is the mod done to offset the increased fuel being delivered via the larger pilot jet, main jet and mixture screw mod (when all are done)?

Here's why I ask- I've been riding with no spacer since shortly after buying the bike.  I've got the 152.5 main and 55 pilot with the mixture screw about 1.5 turns out.  I've since added the new exhaust which has a baffle that serves mainly to effect sound and not really add much backpressure.

With this setup, I'm wondering if I should add a single #4 washer or if I should just leave it alone.  It's been a while since I checked my plug but it was fine when I did.  

I forgot that part about the spacer.  I was sitting here thinking the needle just runs through the spacer but actually the needle has a little shoulder or something below where the spacer goes and the spacer rests on that.  The spacer therefore pushes it down further.  

Thanks.