What type of paint should i use on the outside of the h440. plastidip or spray paint or others
I'd personally go with automotive grade spray paint since you get more color choices and more vibrant or bright colors. Plasti-dip is good but don't forget that it us a rubber based coating so it lacks contact pressure or abrasions so it can scratch or rip easily.
I have a write up under the Painting section of this post that goes over plasti-dip in detail: