How to make homemade cooking spray
For several years, I've been putting canola in a plastic squeeze spray bottle and using that.
I do not recommend 'vegatable' oil, which in the USA is usually 100% soy oil and I have found that it gums up and can leave a difficult to clean residue

Yes, my system can apply too much and do so unevenly too. just use a paper towel to wipe off ecess and even out.

Far cheaper with canola priced at about $5 per US gallon versus 8 oz of generic aerosol spray at $1.99