[gafftaper]

I live in the land of earth quakes so "the big one" is always a concern. Although if the subduction zone out here goes off with a 3 or 4 minute long 9.0+ quake like they keep threatening, a few falling lens tubes would be the least of my worries. Thus some shock cord, or as you suggested doors or sliders are a good idea to hold things in a cabinet.

Unfortunately there is no out of the way space in the catwalk. It's a 3' wide path and that's it. There are no hanging positions or circuits accessed from the two end walks, only the center cross overs. So the end hand rails is where spare instruments will hang and in theory it's a good place to store other items as long as it doesn't take up a lot of room. Yes there are 1 1/2" hand rails and vertical support rails all over the place so it's easy to connect something to the catwalks just about anywhere. There are also lots of exposed I-beams above that could be attached to as well.