^What's that for? He made a great port map.
It probably is the rust from your tank making your plug red. Do you have an in-line fuel filter?
You need a colder plug if there's any evidence of pinging, you need a warmer plug if you're always fouling your plug. I run the coldest plug I can without fouling; I've ran a B9HS and never fouled it. Timing should generally be okay at the stock setting. You might get away with advancing it a bit, that will give you more low-end at the cost of higher cylinder temperatures.
If I were you, I'd just crack the case open and check everything. Replace the seals and bearings as soon as you can afford it, it'll save you a lot of headache later on. I'd replace the crank when you replace the seals. Treats has a great Tomos performance crank