Hi paxNoctis,
Welcome to Cliffs of Dover.
At least you've gotten your Spit in the air -- kudos! I'll be glad to give you the "Coles Notes" on engine management for the Spit 1a and 2a, much of this applies to the Hurricane Rotol as well.
First, turn Engine Temperature Control "ON".
When you take off, throttle should be wide open, Prop Pitch Fully Fine, Mixture Full Rich, Radiator Full Open, Flaps Up.
When you're up and climbing, immediately pull your Wheels Up, then slowly pull back your Prop Pitch control lever to drop your rpm's to 2500. Leave your throttle Wide Open (which gives you 6 lbs boost; if you took Naked Squirrel's excellent suggestion and opened the Boost Cut Out gate, you'll be at 6.5 lbs boost -- which is even better). Now close your radiator 50% (half closed/half open). This will give you your top cruising speed without blowing your engine, plus an excellent climbing rate.
The next thing is to trim -- you can use your slip and yaw gauge to judge your trim for least amount of air drag; basically just adjust your trim so that you can hold your climb, level flight, or descent with your hand literally off your stick. If you have trim wheels on your stick -- great. At the very least, be handy on the keyboard to frequently adjust trim to give you your maximum speed.
In this sim, the Spitfire IIa is fastest, followed closely by the Hurricane Rotol, followed by the Spitfire Ia as a distant third -- which is incorrect but hopefully will get fixed in the next patch.
Good luck and let us know how it goes.
EDIT: Better yet, do what SEE/Evangeluse does: he has a higher kill record than I do! LOL