I haven't used palm oil on my hair since November 2011. I did have AMAZING results with it. My hair felt so soft, moisturised and looked so beautiful. However, it was a horrid process to wash out the palm oil (took forever!).
Palm oil should be used as a deep treatment to combat dryness and not as a leave-in in my opinion because it can stain things and the body heat that aids the treatment helps your hair absorb what it needs from the palm oil better than if it was used as a leave-in.
Would it be too much? It all depends on how much of it you use (my advice is for you not to use too much).
By the way, the palm oil I used is 100% natural, my grandmother (dad's mum - black) got it straight from it's primary sellers in Africa so I'm sure of how natural and pure it is. Also, it's a reddish, orangey, yellow colour and if it's heated up, it melts to look like a coloured oil.
Things I use: Olive Oil, Canola oil, rosemary oil, aloe vera gel, shea butter, mayonnaise, eggs, milk, bananas
Everything I use is 100% natural. I make most of them myself because then I'm sure what's in it and I'm sure nothing's added, it's pure, it's natural.
Things I avoid: Mineral oil (codename: Baby oil), heat (I'm a total, no hair driers, no straighteners, no curling irons, no flat irons, no hot combs...nada), sodium chloride
Growing plan: At least 6 inches longer in a year.