OK A shock absorber is most efficent when the action is at 90 degreese to the movement the more angle the less movement in the shock, that being said vertical shocks limit travel especially when you want to lift your 4wd.
This can be worked around by getting a firmer shock or adjustable shock and mounting them on an angle.
As for what direction is better forward back in or out (yes you can mount the shocks to the middle of the diff but they really dont work there they are working on the body that way) you need to look at where you have room and can balance it on the other side, the best position to attach the shock to the diff is at its most outside point practical, as for the top this is a best fit situation but if the mounts are on the back of the diff when the diff goes up the shock top mount has to be out of its way (don't place the shock where it will cross over the diff I am sure everyone figured this one out but thought I better put something here
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My preference is to go for a slightly / \ style but I have one shock mounted on the front going forward and one shock on the back going back (matching distances and geometery) on the back and vertical on the front
Also be carefull with mounting shocks there is an up and down to them if mounted upside down most will deteriorate really quickly and remember when you jack up the corner of you rig to get compression you are only picking up essentially that one corner or maybe up to 30% vehicle weight, when going down hill like you can encounter up to 85 to 95% of the weight of your rig, allow for this in travel compression this is usualy when the bump stops met and 85 - 95% of the weight of your truck on a shock mount usually ends up in a bad way.
Good luck and post after pic's so we can comment on your welding
and shock positioning
) I was to change about my rear shock mounts are there any rules of thumb to get them to work properly as to straight up & down, forward slant (Range Rover), sideways like a GQ etc etc.
so tomorrow evening I can get some measurements...
