I use VP Racing Golden Break In fuel 1 quart then go to VP Racing Basher Fuel for bashing (it is easy to get a base tune with and will never run hot unless you are really lean) and 25% VP Racing for racing.
https://vpracingfuels.com/product/golden-break-in-14-oil/?c=248
That Losi is great, if you take your time to run it in and look after the basics you'll have a really reliable car to play with, they are super tough and easy to work on. Congrats!