Have you checked out the help on the Import 1099 Beginning Balances screen?  On that help screen, it details the format of the import file which is a text based fixed length file.  I just tried it on our upcoming 2019 version and it works.

Treat each field in the import as a text field.  So if a vendor ID is "V001" then the vendor ID field which is defined as 12 characters, you would specify "V001        ".  If you are referencing a box such as box 5, use "5  ".

You can delete beginning balance entries, but it is painful using the UI as you must do it grid row by grid row.  I suggest you import a single record and decide if you get the expected results. If you do not, delete the single grid row.  When you are satisfied, do the full import.

Keep in mind that the vendors must already be in the system and must be defined as a 1099 vendor (specifically must have a 1099 type of business or individual).  Also, it appears that the error logging goes to the tciErrorLog table, and does not have a form or UI to display the errors, so an SQL query to that table must be done to see the log entries.  

We hope this helps.

Ah, digging a little further i found the record layout link! Here are the fields needed, and their respective lengths. From your post above i guess any excess space has to be taken up with spaces after the actual data? i don't see anything about that in the help file, so good to know!

VendID - 12

Year - 4

V1099Form - 1

V1099Box - 3

BegBal - 16

Thanks!