That's a hard question. What kind of finish do you want? Flat? Glossy? Satin? I tend to use flats and satins to be in scale and historically accruate. I will use glosses when I want an artistic, decorative finish. You can use just about any medium from enamels, to acrylics, to oils. I base prime with an enamel primer, then use acrylics because these are easy to mix and safe. I use oils and pastels for weathering, aging, or to give the model a shaded / heavy look. I tend to go with a laquer clear coat satin to protect the finish and give the model a uniform sheen.
Far as brands, I use them all; Testors, Humbrol, Tamiya, Guenze Sangyo (Sp) Floquil, Deco Art, Badger, Blick, Grambacher, the names are endless.... these are all safe for your Heller kit.
Scott