J.R.
Hi Rachel,
here's a link to a site i frequent when starting solids. I used this as a guide for my son who is now 15 months and it seemed to work out for us at about this pace, though, i never pushed it on him if he didn't seem to want it. I think at about 6 months your baby should be able to turn away if he's truly not interested. This site speaks in terms of 'cubes' for food, because it's a site for making homemade baby foods that you freeze in ice cube trays. If i remember correctly, 1 'cube' equals about a half jar of stage 1 foods.
http://www.wholesomebabyfood.com/babymenu.htm
of course, there are disclaimers that you should not necessarily follow their guide as a hard/fast rule, more so as just a guideline, and to listen to your baby's cue's for his individual appetite. I always cut back a bit on the solids if it seemed to be taking away from his formula intake (I always kept a log of all feedings, with time, ounces and a running total for the day so i knew if his intake went down, and also to note new foods and any reactions)
have a great day - hope the site helps you :)
~J.~