Here is my input on these radius arms.
Vehicle: 1997 LX450
Suspension: 2.5” OME lift, heavy front, medium rear, with OME caster correction bushings
Wheel to fender measurements: 23.5” all wheels.
Caster measurements prior to Delta radius arm install: Left: -0.8 Right: -0.7
Caster measurements after Delta radius arm install: Left: +3.2 Right: +3.4
Delta Radius arms: 4-inch with Toyota OEM bushings installed
I bought and installed the 4-inch Delta high clearance caster correcting front radius arms. Install was very straight forward. Thanks to suggestions in prior posts in this thread, I used a ratchet strap and a jack to move the axle around in order to line up the holes, which worked great! My install time was about two hours, but it only took that long because I forgot that I needed to move a car from in front of my cruiser, and only realized my mistake after dropping one of the factory arms. So, I had to put it back together, pull it off the jack stands, shuffle cars and start again! Gotta love an idiot move like that! This is an easy after-work job in the driveway.
Some of the math related to this little project turned out a little odd. OME caster correction bushings supposedly correct 2 degrees. My caster with the caster correction bushings in the OEM radius arms was -0.8. The 4-inch Delta arms correct 8 degrees of caster. So, I would have expected my caster after install with OEM bushings to be roughly +5.2 degrees. The actual end result averages +3.3 degrees between both wheels.
Thanks to the Delta guys for recommending I go with the 4-inch arms.