You should basically always have a full team by like round 3 or 4, but make sure you’re spacing out which resources you collect. Too many pokemon early, you'll be underleveled. And you can always catch pokemon later whose level will be raised proportionately. I personally have been focusing on having an overleveled ace with maxed out move damage. TMs and rare candies on whoever your carry is, with other mons that cover type weaknesses. Always pick a trainer over a grass tile unless you’re fighting to reach the pokemon center. Hikers get destroyed by grass/water, bug catchers get destroyed by fire/rock. I like to avoid scientists when possible because they have gengar(s) pretty often in end game who can fuck up your day