Ideally the wheels should have been cleaned and have an Isopropyl Alcohol wipe down before application.

What to use to apply? You want something that is soft but also something that isnt very absorbant, as if you used a regular applicator, it would soak up a lot of the product; not ideal. Cotton pads that the ladies use to remove make up would do the job, or a piece of material such as a cloth that would be used for cleaning a pair of glasses, is the sort of thing that would be ideal. Soft enough to spread without damaging the surface, that will take liquid, but without soaking up lots of products.
There isnt really an applicator on the site that I would recommend; I havent had the time to source the ideal applicator since the Wolfs range arrived a few weeks ago!