Hopefully somebody else chimes in about Smog testing rules. I live in a "do whatever you want to your car after you get your safety" world.
Air/Fuel ratios can be shown to you on a gauge that gets its information from a wideband O2 sensor you purchase (you want a wideband sensor with a digital gauge). B&M makes a nice FPR, and usually it comes with a gauge when you purchase it on eBay. However, the Air/Fuel equipment will be expensive (probably in the $200 area), and the FPR/gauge will be over $100.
But they are all required equipment when you start modifying the motor like you already have (the FPR less so, but it helps in tuning...cheap builds use it as the only tuning method, but the most of the tuning needs to be done at the dyno using your P28).
Timing can be set with a timing light by a mechanic. But, all of your problems should go away if you go get a proper tune from an OBD1 Chip tuner.
Your $200 budget won't cut it in the long run. Think closer to $600ish for all parts, tuning, and dyno time.
The fastest fix MIGHT be to increase fuel pressure with the FPR, but you'll still have the CEL problems, because it's probably related to your P28 tune.