Oil Undercoating Help Please

Do most people oil undercoat their trucks themselves or do that take it to someone. I do have a Graco Airless Sprayer and I am quite sure I could effortlessly undercoat the frame, I am just not sure how to get the oil in all the areas it needs to be. (I am told most places also get the oil into the rocker panels and other areas as well). Oh and when is the best time of year to do it? Thanks.

 

I did the Fluid Film in my yard with a cheap HF sprayer.

 

Is it a liquid and where can you order some? I'm guessing it would go through the airless......any advice on spraying it inside the rocker panels? Really kind of new to this.....or better to just hire someone each year?

 

http://www.fluid-film.com/

I did use an airless gun.

 

I see Grainger and Lowe's carries it, do I need to take off any rust prior to spraying?