First of all, Chris, welcome to the PB Forum.
You mentioned "....in very large type. I find this distracting as the same items are are part of the center screen...."
Two comments, for what they are worth: "...very large type." You can change this by pointing to the active thought (the one in the centre of the display ("Plex" in PB-speak)) and then rolling your mouse wheel. One way will enlarge the type in all visible thoughts, the other will reduce it. This may help.
The other "...the same items..." If you are just starting with PB you probably don't have that many thoughts in the Plex yet, so they're all visible both in the centre of the screen and in the past-thoughts list. In these circumstances it is, indeed, all a bit redundant. But as you add more thoughts to the brain you are working on you'll probably find that they don't all stay visible all the time. In these circumstances the past thought list can be a useful shortcut back to a thought you've activated fairly recently, but which has now disappeared from the plex. Note that you can scroll the past thought list 'back in time' by pointing to, and clicking, the left-pointing triangle between the Search button and the leftmost visible entry on the PTL. HTH!