Best way to import large project plan from Excel file?



I have a project plan containing 140+ columns and hundreds of rows that I would like to import into Smartsheet. The "Solution Center" import breaks every time in the middle of the upload. As this is a large file, I assumed running a data shuttle would be better. The only issue is, the data shuttle seems to require I individually map all of my columns 1 by 1 to the sheet. I would like to just populate a blank sheet with the data from this file (less than 2mb) without having to add 140 blank columns and individually rename all of them.

Other issue, when I want to add columns to the sheet, it seems like I can only add 5 at a time? To add new columns I need to highlight more columns, thus creating this weird feedback where you need columns for more columns, but you only can do up to 5?

Am I just missing something here? I really hope I am.