You would be the first with flatsides. You need an independent wideband o2 sensor. You can get somewhere close with 600 rmk Polaris carbs. First, find the main jet when wide open throttle (WOT) that puts you in the 13:1 air fuel (AF) ratio. Starting rich saves your pistons and cylinders. At idle AF ratios really don't matter, too lean and the motor just wont run and too rich is just costing extra go juice fine tuning here gets you out of the hole with power. Mid range is the difficult bugger. Needle jets, Jet needles Throttle valve cut or pillow.... Always stay rich > 14.7:1 always. Motors put out more horsepower in around 13-12.5:1 AF
You can save some disassembly putting in jets with a tempaflow manipulating the altitude screw to give a margin that covers multiple jet and step in the correct direction to approximate how far you can change the jetting. This lets you skip thru lets say 50 points worth of jetting.
Near sea level, best to start with 500 mains at least.