500t mate with master of towing(limited)

I currently hold a 500t mate inland license. I am trying to get my master of towing(limited) on a limited route. I hold a completed TOAR with over 30 days sea time as well as 90 days of training and observation on the route. From my understanding this is all thats necessary. Does the 90 days need to be before or after the toar is completed or does that matter. Also I read with a towing endorsement nothing has to be submitted just have to have a sea time letter and toar on hand. Is this correct?

I believe you are correct, but without the actual towing endorsement in your MMC you will be at a competitive disadvantage in the job market.

Thanks for the reply. I plan to get it on my mmc. Was just curious if it needs to be in the mmc before I work as master or if the sea service letter and toar is good on hand until I get the sticker.