Bob,
Not with regard to FTF, but I believe you've added a touch of overlap to previous 50/next 50. I want you to know I appreciate it. It was difficult to be SURE I hadn't missed a message when I needed to go beyond the last 50.
Today, when I came online, I was 70 messages behind on Zeev. After reviewing the previous 50 and noting the message number and time so I could check the next 50, I found that Next 50 showed two messages as "already read". A blessing for me, and my blessings on you, Oh Fast-Fingered Wonder!!!
Fred