Proper jet size

[Codoloco]

Hi,  my setup is a 91 GS500E slingshot with a slip on universal muffler http://www.bikebandit.com/aftermarket-parts/motorcycle-engine-and-exhaust/exhaust-accessories-universal/helix-universal-muffler?m=16075   Its actually 4 inch's shorter and pod filters http://m.ebay.com/itm/4x-60mm-Air-Filter-Cleaner-Pod-For-Honda-Yamaha-Suzuki-Kawasaki-ATV-Scooter-/152156775561?nav=SEARCH

Just wondering if anyone has had this setup or close.   Was looking at a few things and I was looking at 40 and 147.5
Just wanna make sure before I but