Some will tell you to put in a F-type four-stroke plug but dont do that unless you have severe reliability issues. The #6 plug is not the hottest, the #8 is the hottest as far as I know. But you should be ok with the #6.

For fuel, you need fuel with 20% lube. Plain castor will do if you want to brew it yourself. Just ensure that the % of lube in the final mix is no less than 18%. Nitromethane is not really necessary in your 46AX. It will give you a more reliable idle but, being a oxidiser, it will cause bearing rust if you dont empty all the fuel out at the end of the season, so I would suggest not to use it unless you have to or atleast use no more than 5%. You can also look at the more expensive synthetic fuel. Ensure whatever mix you buy should have some amount of castor. For example, Klotz 100 available of Tower has 20% castor in the Lube and you can use it to brew your own fuel. This will ensure lubrication even when no fuel has reached the carb at the start of the day.

The 46AX is a very strong performer just as long as you run it in properly

Ameyam