for the 360 deg. X axis I had planned for rotational clearance for a full 2 revolutions.
Just bear in mind that the wires have to do the same, so sorting them out will be the biggest issues here i think.
For the 180 degree y axis, I chose 180 degs. For ease of use. (being parked on a slight incline may possibly give an angle grater than 90 degs.
If this is to be used in Norway then I suppose an angle in the 90 area may be required, although I suspect there would be so little solar energy that it wouldn't help much. I'm just thinking of the mechanism, 90 is one thing, 180 can be a very different thing. I would think 100 would be the absolute max required, especially as most people take great pains to get their vehicle level.
how would I do that and still be able to control them?
If you switch the low side of a motor the voltage used to drive it has very little effect on anything, you can have 12v powering the motor and switch the other side of the motor to GND with a suitable transistor or relay.
From a single solar panel up to maybe 8.
This is a problem IMO, 8 solar panels is a huge area with a lot of mechanical advantage over the pivot point. The wind loading would be immense. I know someone who has done just this (on the ground, not a MH), he used a car rear axle and diff as the mechanism and that was braced a couple of feet up the axle. Possibly over kill but don't underestimate the force of the wind on these panels.
I know another person who has a tracking system on a motorhome, he does have 8 panels but has to put it down if there's any chance of high winds.
For a single panel I think there is already a product that does this, certainly the sat TV people have the same requirements and they solved it years ago, mostly using GPS I think.
Also you have to think of the loading on the MH roof when the wind blows, most MHs are made form cardboard and staples, they will not stand much force being applied to the roof materials. It's typical to add steel bracing for air conditioners, you may have to do the same.
I've been living off solar in a motorhome for 13 years, in all that time I've only ever seen a single tracking system (the bloke I mentioned above), the general school of thought is that it's better to just add 1-2 more panels because the tracking only gives you 10-20% improvement overall anyway (depending on latitude of course, huge gains at the poles, almost none on the equator). Of course if you don't have the roof space it's not possible to add panels and tracking becomes more appropriate.
So I see the mechanicals as being the hard part, the programming should be pretty simple and there are a 1000 examples on the web, probably half of them open source. I'm more a fan of the RTC/GPS approach because it doesn't care about bird shit on the sensor or overcast days when your LDRs can't pick the difference. Although I suppose you could argue that if the light is that diffuse it doesn't matter where you point the panels. Your code will have to handle the case of a sunny day with a few clouds, ie don't go hunting just because the light fades for a while.