It's always best to build dots from day 40 through day 48. With GLB having age based leagues as you work your way up through the system, it's best to build them during that time. Not sure if you just came back to the game and didn't know this so I would say, play around with those dots you've built, check out different strategies to build dots and then retire them at the end of this season.
You can still advertise for your team starting up for season 53, there are always people looking to get on a human owned team, or guys looking to stash a few extra dots for later use. Put up a positional thread in either this thread or your team forum to keep track of recruits and the positions they're willing to build. This will also help you in knowing which positions to build yourself when you create your new players.
Good Luck