Either or will do the job. I usually use aerosol as it's handier. Just give everything a good rub with a wire brush to take the rough off then clean the dust off and spray away. Don't worry if you get a bit of paint on the disc, first time you dab the brakes, it'll come off.
i use an aerosol too... i wouldnt worry about heat resistant stuff. your brakes will not get hot enough to ruin the paint. mines are red atm and they are still as good as they were 9 months ago.
a nice yellow would be nice against the blue lad imo