If your bridge is in balance and you land the bridge on the
stage and pull just 10-20 pounds more, the bridge will stay in place. Add non skid pads to the bottom of the bridge to increase the holding force. "All the weight" is NOT on the
arbor side, just the few pounds you "pulled". The only way to put "all" the weight on the
arbor side is to have a
stage hand(s) that out weigh the bridge and to pull until the lift lines go slack. DON'T pull until the lift lines go slack!!!! You can pull up to 50 lbs over balance on a standard rope lock. In fact, very large stages with 60
foot long battens and
grid heights of 60 feet of more can experience up to 100 pounds or more, out of balance in both directions, in the normal use of any
line set, if they don't have compensating chains.
Bottom
line, you should be fine as far as weight and balance are concerned. The only problem you might encounter is lateral movement as talent steps (jumps) on or off the
unit. If this becomes an issue, use a
cane bolt and a
block. i.e. put the bridge where you want it. Determine which direction the
unit wants to move during the action. Put a 4" long piece of 2x4 against the
unit, drill a half inch hole and insert the
cane bolt. The
block will stop the lateral movement but allow the
unit to fly at any moment.
Depending on the type of rope lock you have, the age and proper (or not) adjustment of the lock, you should be able to easily pull up to 50 lbs out of balance. Now, do not think that I advocate or advise to use
line sets out of balance, I only want to
point out that in the normal course of things, every counter weight
line set is a little out of balance. The
Clancy SureLock and the Tiffin Restrictor both "lock" when out of balance loads exceed 50 lbs. The RESTRICTOR is rated to hold 1200 lbs out of balance, the
HAND LEVER is rated to hold 1000 lbs., the "CAST
IRON" rope lock is rated for 150 lbs. So, as you can see, some degree out of balance is actually a "normal" condition in a counter weight
line set.
Hope this helps.