Pausing before macro

I have a workbook that I need to

1) open at a specific time each day,
2) grabs some information from Bloomberg (updating takes about 15-20 seconds after opening the workbook)
3) and then run a macro after the updating is finished.

Right now I've:

1) created a batch file to open the file
2) set Windows Scheduled Tasks to run that batch file at 4:15pm
3) Created a workbook open event that calls my macro if the workbook is opened between 4:14pm and 4:17pm

What I'm looking for is the best way to pause before running my macro until the workbook has been open for say 30 seconds.

I have read through a lot of threads asking this question, but the threads have not been marked solved, and it seems that a lot of the proposed solutions have the problem of pausing all activity in the sheet, so the information from Bloomberg doesn't update while the macro is paused.

I'd appreciate any help on the best way to proceed.

Thanks,
Dylan