Well, filtering to just file path occurences will clarify the "count / quantity" of files to be restored.
But for the size of all files to be restored...
...my tip would be to use these two additional switches on the bplist command:
-l -b wide list, and the date shown is the file backup date
-l -c wide list, and the date shown is the file create date
-l -u wide list, and the date shown is the file modified date
And so, with a "wide" listing you will also get the file size in bytes, or in K, e.g.:
101 = 101 bytes
202K = 202 KB
Also, look at using: -listseconds on your bplist command. You'll see what I mean when you spot the differences between using this switch, and not using this switch.
One nice thing about the "wide" listing is the predictable column layout, so... you can still always pull the full file specification, e.g.:
volume:\folder name\subfolder name\my file name.txt
...from about character/position/column 59 or thereabout to end of line.
I think you will definitely end-up needing to use findstr /v "\\$" or it's PoSh equivalent, to filter down to only files being restored, because you will most probably NOT be wanting to send a restore request to NetBackup of a folder path - otherwise you may very well end up with a whole bunch of extra trees/folders/sub-folders and files being restored that you will most probably do not want to have restored.