Ok, here's my take on it, but I must stress here I am no expert and am just trying to look at this logically.
There are a few factors that influence the tyres: -
- The type of rubber - with softer typically giving more grip and harder giving less (Blue = hardest, Green = hard, Yellow = softer, Silver = softest)
- The tread pattern - how much contact is there between the rubber and the surface? More contact = more grip (Rule of thumb - pins = most grip, spikes = next, cut staggers = next and finally staggers. Obviously there are other like blocks etc but I've never seen them run)
- The surface being run on - high grip / low grip
If you then bring in front tyre profile, low profile tends to have a squarer profile so will have (depending on tyre vertical camber) good contact in a straight line, but less contact on turns - good for higher grip (I've heard it said though that the shape also helps with initial "bite" on turning as the square edge digs in, but this is opposite to what I have said and what I think. Guess it needs something to "dig into"). Normal profile tyres give contact in a straight line as well as on turn so is better as the grip drops
For rears it can be influenced by the inserts - softer = more tyre "squish" so more contact, harder = less squish and contact
Usually on a slippery surface like dusty dirt, you need as much grip as possible so I'm told "silver" is used but never driven on dust so can't comment.
On a slippery but non dusty surface typically mini pins are used as they have more individual points of contact and normal profile fronts give even grip through turns. This may also explain why often "worn" pins work as the wear on the points will give a greater contact area.
On decent grip astro you then tend to move to LP fronts with less "tread grip" (so cut staggers or staggers) and pins or spikes on rear
I've heard it said that yellow mini spike rears give a good general level of grip and are more forgiving, although not always the absolute fastest tyre on any given track.
I also was talking to Richard Lowe a week or 2 ago who was saying similar about Ballistic Buggy Greens for outdoors. I know they tend to be seen as the wet weather tyre, but are apparently a decent all rounder outdoors - can't comment as I've not tried them in this context, also I'm probably not good enough driver to notice. (Do not use them indoors though as they are rubbish!! - I can notice that when I accidentally use them)
There are websites out there that can give more detail which I will see if I can find links to