got me motivated. found the 43 and 70 were at infinity focus a bit before the stop (about 1/8" -3/16"on the barrell) implying the back needed to be a bit farther away.
with the cambo, you can move the back by removing the four screws at each corner and screwing in the bushings a bit. took three attempts, sneaking up on it, altogether about 90 degrees rotation per bushing (see the cambo tips link)
then put on the 120 and found it was not moving quite far enough to reach focus at inf, so used the info in the first link to adjust the inf stop on the lens.
did this tethered, IQ 160, image size 100%; hardest part was finding the perfect target. distant tree limbs against the sky were not so good, same for a distant antenna. ended up using a fire escape against a not-so contrasty background.