I found a guide with pictures for proper spark plug color, take a look and tell me if you think its a good guide,

also, which plug is better for reading on the ds, inside or outside(closest to header)?

 

I like having pics to compare too. I tried reading the plugs before by following the full out test run (carb 101), holding the throttel wide open while hitting the kill switch than coasting to a stop, pull the plug and check color. It didn't seem to matter how I jetted, it allows looked good even if it ran bad. Wish I could see it done properly, just felt like I was wasting most of an afternoon when I tried it. I just pulled the easy outside plug, maybe having two complicates things.

 

I think I've heard the inside plug is a better reading, which kinda sucks. Jetting is kinda a pain. What I've done to jet in the past is not so much a 'plug chop' like DaSandBomb was doing but if I was trying to jet the main jet (high RPM jet) I'd install my selected configuration, go and ride for a few minutes staying in lower gears so that I could easily stay in the high RPM range thus really testing the main jet. If it runs horribly you go up or down a jet size & see what happens. The main thing is to concentrate on just the area you are trying to test. (Top end for main, mid RPM for needle & low RPM for pilot.) I would run it & see if it ran well, once it started running well, I'd only then start checking the plugs because if it doesn't even feel right it doesn't seem worth the time to check & see how badly the plug looks unless it's out of curiosity. I found that with a few more jet changes after I found where it ran well, I'd come out with a pretty decent running machine which was much more powerful than when it had factory jetting specs. (I had run the machine with a pipe on it & not changed the jetting for a while a big no no, however rejetting showed A LOT more power!)

I think the pictures on that web page are straight out of a Hayes auto manual I've seen - or maybe everyone uses the same 'reference' pictures.