SU Carb Needles/Jets

[Redneck Rocket]

Hello all. I considered posting this in racing technology but it didn't seem terribly technological and I thought I might find more expertise here! I've finished the engine build on my Spitfire and driven it about 100 miles on the road. I upsized to 1.5" SU's from 1.25" that were on the car. It has a 280 degree cam, full 4-2-1 manifold & exhaust, fan replaced with electric, head skimmed to give 10:1 compression and 3 angle valve seats. I'm concerned that it is running too rich and needs different jets and needles. Not being a rich man I can't afford to take it straight to a rolling road and pay them for an hour of their time, although I will have to pay someone to set the ignition timing correctly. Does anyone have any practical tips for setting up the carbs and getting the right needles/jets?