shock efficiency and mounting bolt direction
 

Maybe late since already build shock mounts for rear relocation.

In regards to shock efficiency. Mounty bolts. Parallel to axle or perpendicular? Seems parallel would be less friction since articulation would have them pivot front to rear or opposite depending. Plus seems moving trailing arms up could cause binding if running perpendicular since angle will be changing. That and I need to thank of this before welding up set of mounts. Not LOL At least have not made top mounts yet. Hoping I am wrong and someone will point out why so do not get to remake them right.

Oh shocks mounted to trailing arm and out side of frame

Re: shock efficiency and mounting bolt direction
 

No matter how you set the shocks. You want them about mid storke for max effect. Using the longest ones with in reason mounted the furthest out you can achieve.

The Square body style is the best for leaf springs due to the way they mount.

ButnI believe you have a trailing arm, and my recollection. Is behind the axle mounted vertical is the best.

Re: shock efficiency and mounting bolt direction
 

Pretty much any shock absorber will react the same (except for specialized pieces) no matter where they are static in the stroke. IME the important thing is not to have shock bottom before suspension or allow it to be a limit strap. This can cause damage.
As far as efficiency, The more vertical they are with the travel will make the dampening stay consistent through movement. Not an engineer, someone who is can chime in. Believe the reason many OEM's angle shocks for reasons other than clearance is that dampening decreases as suspension compresses. This makes for a more comfortable ride.
As far as which way the bolts point in shock mounting. Doubt it matters much on a stock or lowered suspension as movement is not enough to matter. I stuck with the stock mounting bolt type with the shocks on my truck. While my situation is a bit unique, would have done the same with standard shocks.

Re: shock efficiency and mounting bolt direction
 

With quite a bit google research and few other sites. Both have benefits. Perpendicular to axle seems to be best for handling. Plu easier to mount outside of trailing arm and very slight angle into frame and 90* to axle up and down. Seems slightly angles in helps with axle articulation too. Top mount allows dbl shear mount which is always better.

While probably minor detail. As crewchife on few pro drag cars I have learned littl thiung add up to big when take all you can get approach is used. Kind of like taking 12oz of car nothing but do it 20 times and you have a hundredth plus and have had dn'q by .002. Now I take all and grab for more.