Okay, I have tried numerous hours using each setting--30, 48, and 256--and what I found was that there is no difference. Behavior is the same. I found one site that would not load at all, yet the status bar said it was almost complete. I found it to load okay with IE. I searched for an add-on that will force pages to load to completion, but did not find any, although there are so many add-ons, I could have missed one. I hope there is a solution somewhere, and for anyone else who might have this problem.
UserAgent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:188.8.131.52) Gecko/20110920 Firefox/3.6.23