I found a simple script to make Safari default to a higher zoom level than default. No more hitting "CMD +" every time I open a new browser window. One simply creates a new text file with the code below, and saves it as a .css file. Then you can have Safari use the .css file as the default settings by going into Safari > Preferences > Advanced > Style Sheet and selecting your .css file. I tried 110% and 115% and settled on 120% for night time browsing and 110% or no zoom for daytime. (in the dark the pupils dilate and old eyes focus worse)
body {
zoom: 120%;
}