Minimum Size Arca Clamp to use with L Bracket

[taxboy]

I'm considering purchasing the 3 Legged Thing Roxie L bracket and in common with many L brackets it has a cut out for the screen. Can anyone please advise the minimum size clamp I should purchase to match this bracket to bridge the cut out gap and retain sufficient clamping force. I understand the cut out slot measures 28mm. My initial thinking is 60mm but would appreciate confirmation from any similar L bracket users

 

[Box Brownie]

I'm considering purchasing the 3 Legged Thing Roxie L bracket and in common with many L brackets it has a cut out for the screen. Can anyone please advise the minimum size clamp I should purchase to match this bracket to bridge the cut out gap and retain sufficient clamping force. I understand the cut out slot measures 28mm. My initial thinking is 60mm but would appreciate confirmation from any similar L bracket users

IMO
Perhaps ask 3 Legged Thing for their advice because as you imply you need it big enough to bridge the gap without putting a bending pressure on the open 'free ends' of the design but not so big that it might be too cumbersome ?