i made them my self did not try and use the space above the wheel arches not much that i can think of that you can use it for. the one with the batt in it has a second space for a little bit of storage fridge power cords extension stuff etc and the one with the compressor is just the compressor...
my second batt is in something similar i have the batt on one side and the compressor on the other matching boxs works fine for me not much else you can use the space for
nothing wrong with your charge rate you will find as your revs pick up your charge rate will increase to a max of about 14.5 average charge is about 13.5 to 14.5 if you are charging above or below that then there may be something wrong but as i said yours sounds fine
mate your uneven tyre wear could be from a couple of things first did you put the tyres on new ? if not then it may be from the person who owned it before you not have the wheels aligned properly if they start to wear from not being done then it is hard to bring them back. a good idea it to...
mate could just be a loose belt does it do it under power some times? and wd40 is proberly not the best thing to be spraying on you fan belt. as tweak said may be a bearing try taking your belt off and spin your idler bearing and see how it feels also check your tensioner may not be working...
the other option is to fit axle blocks that way it does not effect your flex but gives you the lift you are chasing snake racing advertises them but heaps cheaper if you know some one who you can get them from about to do mine that way
mate gotta ask where did you get your reduction gears from and how do you find them? i find that low first seems to be not quite low enough and you still gotta hold a few revs to get you up some things? your thoughts would be handy on this
gotta ask how do you guys go with your body lift and insurance ???? i have been told you cant lift them due to having air bag and still be able to get insurance i would like to do mine but that thought holds me back