After doing a bit of research on the forums, I am still left with some questions about my shifting habits and what gear ratios would work best for me.

First off, my riding habits are 90% pavement, urban to suburban, hilly (SF Bay Area), and usage varying from basic transportation, to running errands, to recreational rides.

The drivetrain setup on my Crosscheck is stock, 48/36 double, 12-25 9-speed cassette.

Most of the time when I am riding, I am in the middle cog on the rear cassette, and I do most of my shifting with the front derailleur, inner chainring for start/stop riding and inclines, outer chainring for speed. Again, I usually keep the rear in place on the middle cog. This appears to be different from how most people use a double. It seems more common to ride using the outer chainring most of the time, and to do most of the shifting with the rear derailleur, then to drop down to the inner chainring when climbing hills. So, I guess my question is this: Is it more efficient to use the latter shifting method? I've noticed that I usually have a much straighter chainline shifting the way I do, whereas keeping the chain on the outer ring and shifting primarily with the rear derailleur results in more pronounced uneven chainlines.

The second question has to do with gear ratios. As I said, I live in a hilly area, and my current setup still has me grinding up some hills in the lowest gear. If I simply switched my inner chainring from a 36t to a 34t, would that make a significant difference, or not enough of a difference to bother?