I just stumbled across the fact that now some of the smaller (i.e. civilised, not party) tents allow reservations online using the opentable reservation platform.
The smaller tents are normally more family orientated, food orientated and if I'm honest, often way more ornate than the bigger tents. Oktoberfest when it started was only small tents, and only after many decades the larger tents appeared with their amplified music.
For many visitors from abroad, this will not be of interest as they just want to get smashed drunk , jump up and down on tables, and all that type of messy stuff, which is what the big tents are there for.
If instead you want to get a bite to eat in a civilised atmosphere, then this might be of interest.
I did a test for a table for tomorrow afternoon in Glöckle Wirt (which looks lovely inside) and there was no issues getting a table for 4 .
Heres the link to all the places instantly bookable online :
And the Glockle Wirt