Getting back to the original question, the width of the side bar of the frame needs to allow some spare room so you can part the frames either side of the one you want to remove. This is to allow you to remove the frame without rolling bees or the queen.
New frames in an eight frame box have about 1" of spare room when all pushed to one side, seems a lot but once all the wax etc happens I still feel short of room at times removing frames.
One problem which British beekeepers face when using our standard hive - the British National (essentially a cut-down version of the Root-Langstroth, with a few wacky features added) - is that it was designed to accomodate eleven frames at 38mm (1.5") spacing, with just 2mm left over (in theory) as 'wiggle room'.
But - over the years the industry has settled on the use of 35mm Hoffman frames, which now leave an embarrassing gap at one end of the box - although it is
just possible with the aid of a shoehorn to squeeze-in 12 frames, but only when they're new and un-propolised. Those 'in the know', fill the inevitable 11-frame gap with a dummy board, which is 'inserted last and then removed first', that is, prior to pulling-out any frames. Those who are not 'in the know' either spread their frames out equally, or leave a gap where there really shouldn't be one - with predictable consequences.
Perhaps you could use a similar 'dummy-board' method with your own hives ?
LJ