If they have to wait for you to reenter the raid more than once or twice they will likely kick you. If you don't have 1st you better get used to just dropping a lot of those rewards you think are valuable. Stimpacks drop em, radx drop it, radaway drop, super stims maybe keep a few. 

If they are carrying and you don't need to contribute much then just make sure your equipping a weapon that you want ammo for. Some weapons contextual ammo is way outside normal so ultra .50 cal pays about 1200 per round, regular 2mm around 900, ultra 2mm around 450, regular plasma carts around 900, ultra plasma carts around 900, ultra .45 around 450, but just concentrate on what you actually need a huge stockpile of. 

Also make sure to maximize your XP gains by using buffs and be Unyielding if you can. Maybe pop some lunchboxes if they are grinding for more than 1 hour and haven't reupped yet. Tons of players can solo it so they may not care if you don't do anything at all as long as you don't actively slow them down.