Mass updating of currently extant records in my personal library by "re-fetching" records they were pulled from?

My personal library consists of only about 110 books right now (rebuilding after a housefire) but for a project, I wanted to get an idea of the dimensions of most of the books in my library, and went straight to LT. The trouble I'm having is that a good number of my books are listed in imperial measurements while the rest are in metric, and some records are incomplete or seem to be giving descriptions of the dimensions of the hardcover for the paperback edition or listing incorrect information in various ways (one book is allegedly 1.98 inches wide and another seems to be 5.5 inches wide instead of the 5.5 centimeters as listed).

I am not super tech savvy at all; I've been meaning to learn Python forever but can't do that or Javascript at all, although I have a masochistic love of tinkering with spreadsheets in in-depth ways that don't involve running scripts or macros, so I'm thinking the latter is the preferred method. The hard part would be mass pulling records for what might amount to 20-30 books, either only selecting for records that are cataloged in metric or just making sure all of the records are filled in that field and then finding a way to mass-convert what's left still in imperial to metric in another step.

Does anyone have any ideas or thoughts on best ways to do this? Can I use the mass import feature on the Add Books tab to do the records pull part? Am I chasing a windmill here?

There is currently no way to export a list of books, update it, then reupload it into the existing books.
You'll need to update each record by hand.