i have a build thread in this section. and on the w56, yes, it will bolt up if you use the tacoma bellhousing, but i've never done it. and i'm not 100% sure if the 2wd and 4wd taco bellhousings are the same.
as far as spring perch width i believe the tacoma frame is 3" wider than pre-taco frames, so the perches on the axle are a little narrower. if you look at my thread you can see how i mounted the shackles. TEAM RAMROD also mounted his shackles like that when he was leaf sprung. he used a diamond housing that was 64" WMS to WMS but i'm pretty sure the perches were stock toyota width.