I just thought of something, actually it kinda shot itelf down when I looked at it again. Say you found a coiover setup with and eyelet top instead of the stud you wouldn't need to use teh rose joint but that makes one problem (two since I can't find any shock like I'm thinking)

1. eylets are bigger so not as much adjustment

You think that is a issue for you, I'm in SA, any non standard part is a issue if the budget is tight.

Good idea on the plates, well done there, I would definitely be going for a larger high tensile bolt and use shims to change castor, also use a larger rod end. Can you buy from ebay US? A lot of surplus race gear on there.

As for measurements, monroe catalogues here in Australia have all measurements for their shocks, good for sizing up different models and makes doesn't state valving, I wouldn't use gas inserts in a datsun myself. Oil is the way to go.

I like the design, my only concern is the strength? How much extra pressure is put on that bolt when you adjust the castor? I would've used a series of holes to calibrate the camber, are you trying to pivot the rosejoint to help with castor? or purely adjusting it at the rods?

i've got the same problem with my shocks bottoming out, i need to go at least an inch lower at the front but my shocks bottom out if i go any lower and this is without bump stops or anything so it's the max travel i can get. with your setup though couldn't you just make your camber/caster adjuster thing taller so that your shock bolts up much higher and you get another inch or so lower without losing any shock travel at all? you could even make them with multiple slots so that these gave you height as well as camber and caster adjustment, although strength might start to become an issue.

Yesterday assembled it with a M12 HT bolt, worked great, will one day when it is in use see if it holds up, otherwise the next step will be to get a rose joint with a bigger diameter, even if this means re tapping thread on the shock.

Castor is adjusted by moving the rose joint from left to right by turning a nut or two on the bolt.

i would be using several 1 or 2mm spacers between the plates on that bolt to adjust castor just to limit movement and i also agree with the several holes instead of one long slot but as a prototype its looking good

Oh crap I should post an updated foto from last night. The rose joint is kept in place with two nuts, so it cannot be moved, at the end of the day it will be two locking nuts.

yea but you also get added strength from the spacers against the side plates

good work dude!
Keep us posted on how it goes.