.. In my experience, as far as the spacer goes, it really depends. Some people have removed their spacer altogether to have their bikes bleed gas out of the airbox at idle without touching the pilot jet(i think the airbox. I know people have reported gas bleeding out of somewhere due to this. No spacer works for my bike but it does better with 1 washer (and i suspect it will do better with 2 washers ie half spacer ) owing to the fact that Im too rich with a 55 bh pilot no matter what else is going on - back to 52.5 w/bh - with that im far out on the adjust screw but i have managed to eliminate the shutoff backfire. 52.5bh and no spacer creates sluggish acceleration. Add to this a 155 main and it makes for an all around crappy ride. So I added a washer ( 52.5bh, 1 washer, 155 main) Mid range was much better but it was very apparent when the main circuit kicked in. Still no shutdown backfire. Changed the 155 to 152.5. Idle good, midrange good, main circuit kick in less evident but still noticeable. Switched the main to 150. This is where I stand now - 52.5bh,1 washer,150 main. I still have just the slightest hesitation on the main circuit. I did 4 plug reads between all this. Once for each circuit and the one im running now which still shows a bit rich. I ride mostly mid range so that tells me one more washer may do me good. I could go to a 147.5 main probably instead but while that may eliminate the rich midrange im pretty sure it would make the main circuit too lean. Only by a bit but Im in no hurry to burn up a valve like some have done. I feel another washer would lean the midrange to where it should be and lean the main circuit just enough. ... it's best still to pay attention to the bikes feel as well as do a plug read for each circuit starting with the pilot and working up. Still going to have to open the carb up a bunch of times and take the tank off a bunch of times. It all comes down to trial and error within a certain range of possbilities and Im not the only one thats remarked that this carb never seems to be JUST right. I believe someone here wished they made a 53.5 pilot and I would agree. Or a 148.75 main. If you're rejetting you're rejetting for economy or power. Suzuki's pretty much played out the economy side so...if your doing it for power you might aswell do it right and get the most seamless transition between circuits as possible, and thats no fun...although for me it became fun. With my raptor petcock i can go from seat on to rejetted and seat BACK on in about an hour with all circuits changed. I switched from no spacer to 1 washer in a friends driveway at a party in the dark in 45 minutes (I lost the remaining bits of lancers jet set. Too much wine). Im pretty proud of myself though.

Dwarf - I'm guessing you'll want to drop to a 52.5 with bleed holes and adjust the mix screw, a 152.5 main, and 1-2 washers. No telling really without doing it step by step. 55, no spacer, 155 is pretty rich all around. I don't think you'll like it but it will probably run. 52.5 ad adjust will probably be good, with no spacer will probably be okay, with  155 main will probably be rich. Add 1 washer and you're pilot will probably still be okay with a mix screw adjust. You're midrange will probably be better. Your main circuit will probably still be rich. Add 1 more washer your pilot may still be good with mix adjust.
If so your midrange will be even better. Your main circuit will be way to rich. You'll feel it bog down at high revs. Switch to 152.5 main. Hows that suit you? Do a plug chop on the main circuit. Still rich? Go to 150 main. Check the plug again on the midrange. If it's lean remove one spacer.

I've been typing and aditing for two hours to try and get this across simply and to be honest its just trial and error...

Update!  My K&N filter came in the mail today and I just had to try it. While I was checking over the airbox, header joints, etc. I found a tiny leak between the header and muffler. So I fixed the leak, installed the K&N, and took it for a spin.  This time there was no after-firing at all, and the lean-pops pretty much went away with the pilot screw 2.5 turns out. Go figure.. I uncork the airbox somewhat, went full turn leaner on the screw, no loud pops, it still runs cooler than stock.  So this setup works with the stock carb:

dyna muffler
K&N panel filter
no spacer
screw 2.5 turns out

From this I learned that either the dyna muffler likes to be paired with less drag on the intake (you gotta uncork both ends anyway) and the smallest little exhaust leak will cause after-firing unless you crank the pilot as rich as it will go.

This setup will be more than fine for now.. until I get my hands on one of those Lancer super-carb kits.