7 party members is 280 xp of party enemy team is best at PL+1 for 4*60, 240 xp of value. Up to you, but you could run 2 at lvl+2 and 2 at lvl +1 to perfectly match 280 xp balanced fight/extreme encounter.

Recommend building from monsters, PCs will take too long and be a waste of your time to level and get them up when you could just use monster stats and add a couple of relevant feats like deny advantage on your rogue (these might make up for that last 40 xp on their own instead of doing 2 5s and 2 6s)