Bosch small cap distributor and regular coil (what you have)- gap at .028". Any wider and they will misfire under certain conditions. Most electronic ignitions- pertronix, Compufire, replace points with electronic parts, don't increase spark power and will use a similar gap. Not until your ignition actually creates a stronger spark (more powerful coil and/or ignition box) can you increase plug gap, and now you can get problems with misfiring in the distributor cap itself because the contacts are so close together. This is why the higher end distributors use a bigger (wider) cap.
A shortened/contoured spark plug socket and 'wobbly' extension (doesn't have as much movement as a universal joint but is much more compact) will make plug re&re much easier.
As well as shortening your spark plug socket (I was able to take 1/2" off mine), a little grinding work around the top will help clear the intake manifold easier. If your plug socket has a rubber inner to help hold the plug, pull it out and cut it down as well. I don't have a pic handy of the spark plug socket, but you'll get the idea from the socket below-
Hope this helps. Al
PS- just had a thought- do any of the tool companies make spark plug sockets in 1/4" drive? Just the ratchet being smaller would be really helpful!