Dude...
Firstly get your diffuse map done...all surfaces need a diffuse map. This is your primary color for the job. From what you are showing is a caucassian skin set up, and your character clearly isnt. So i would suggest getting your refs of african/dark skinned people even good hi res shots of Pete Tosh. Then spend a few hours or a couple of days just creating and perfecting the color/diffuse map to the best of your ability. Its not something to rush.
Then from there start building up the scatter layers using the diffuse by altering the color map. As this is an arnold render I really cant comment on the nature of the shader setup or the renderer as opposed to the awsome Bruce Lee one which I recall is all mental ray, so it may differ a bit, so bear that in mind.
What I do know is that once you get sorted in Arnold...theres no going back as its probably the best renderer out there right now...it handles polys by the bucket load so you could actually sculpt some more tertiary details on the mesh rather than leaving it up to displacment. Im working on a wachowski (matrix dudes) movie right now and I can tell you we are using arnold to render some seriously hi res models...they render very quick too!!! Arnold is an absolute poly grinder..it loves them!!
cheers
Jay
yes well i just finished my model, and is gonna add some displacement to it (or as you said just straight up polygons, if my computer can handle that 
) 
Might sculpt the wrinkles and detailed bodyparts and then leave the displacement for the pores and deeper details (?)
hmm yeah i love Arnold, its awesome. been looking through hours of tutorials this last month and i cant stop from being surpriced about how sick this render engine is.
However on topic i dont see how having a finished model matters, this question is about preparation, since ive never really experimented enough with Arnold's SSS layers and since i cannot find any tutorials on the web for how the SSS for a black man would work I just cant get the picture of how the shallow, mid, and deep scatter would work for this type of human. Should i have a very dark (blackish) shallow scatter, should i have a more brownish (light/dark brown???) for the mid scatter, and for the deep scatter i assume its pretty much the same as for a white man...
thanks for the reply 
ill do some experimenting with the SSS once im done with diffuse i guess