Okay lets look at the readings one by one and what you can do to help it pass. Lets start with loaded. High CO (partially burnt fuel) means it is running on the rich side of things. Lean it out by putting a smaller jet in it. I would lean it out till it starts to get a little pop out the exhaust on cruise then move up a couple of sizes. DO NOT DRIVE IT FOR EXTENDED PERIODS THIS WAY it will probably damage a piston. If it misses under load your HCs will go through the roof.
Next Idle
The HCs are high which is unburnt fuel that the CAT isn't taking care of. The Cat is designed to be close to the header and can be too cool. Your COs are low which indicates its pretty lean. I bet the cam is what is causing the low speed miss which would drive the HCs through the roof. Since its a Slanty I guess its a solid lifter cam. I would loosen the lash to mellow out the cam. I cant tell you how much because it will be up to you and how big your sack is. I also would run the timing a little retarded that will cause the exhaust to run hotter and hopefully get the cat up to operating temp.
Once you get to the station ask the Mechanic if you can run it around the block and start the test immediately when you return. Then run it around the block in first or second with the RPMs up to heat the cat. I hope this helps. When I used to have to go through this in Ca when my turbo Dart was runnning I would put my stock 273 back in it for the test. It was about 4 hours worth of work but it worked every time and was really less stressful.