'Rake' is the proper term for a mast leaning back. Typically you want a little bit of aft rake. The rake controls the helm balance (if the wheel loads up a lot when sailing upwind you may want less rake, but I think this is not likely with a furling main). If you want to see some real rake, find a J/boat in your marina. Most of them when set up correctly measure the rake by how many FEET the mast tip is behind the base.

Are you asking about rake or prebend? Rake is essentially the overall angle of the mast relative to the horizon. You control rake with a combination of forestay and backstay (loosen forestay-take up backstay to rake back, etc.). Raking back increases weather helm. Prebend involves bowing the mast back into a slight curve. You induce prebend when tuning the mast. The C36 mast section is pretty stiff but can be prebent by loosening the aft lowers, then taking up both the forward lowers and the backstay. A little prebend helps to prevent the mast from pumping. Prebend also affects the shape of the main so check with your sailmaker if unsure about how much.

If you have an in-mast mainsail, the mast should be straight.
John Meyer

Since I think you said that you have fairly loose lower shrouds, you would have little pre-bend and the mast should be fairly straight with little bend. The C36 should have little rake. If the mast is raked aft, then that would tend to give you severe weather helm. That means in moderate to higher winds the boat would want to round up into the wind and you would be fighting the wheel.

Since you have a very non-standard rig, all bets are off and the previous owner might have given it some rake to counter some difference in your rig. The only way to tell for sure is to go sailing in winds over 15kt and check for excessive weather (or lee) helm. I like to have around 1/4 turn of the wheel weather helm in 15 to 18 kt of wind when going up wind with no reef. Most of us with standard masts don't feel the need to reef the main until around 20 kt.