Tuning a speed density system with mods

[Fostang]

I'm new to efi systems ever since converting my fastback but since my conversion with MAF didn't work correctly I switched to speed density and it worked better than with MAF. Now my concern is that the mods that I did may cause some problem with speed density. I opened up the TB induction because I'll be putting on a 65 mm tb sooner or later but has a 58 now. The upper and lower were gasket match, the lower was gasket matched to the heads, the exhaust side was ported, long tubes were installed with 1 5/8 primaries no cats with full exhaust is in place, smog equipment was removed. What should I start by checking or playing around with till I get it right? The idle seems to slowly come down after reving it and stays at 1200 rpm then drops to 800 and then back to 1200 rpm after a while then back down. The engine shakes a little but not as bad as when running the MAF. So any tunning ideas? Oh yeah and one last question is the right O2 the drivers side?