Ok, so you can only have 1 of your party to kill bosses as now you have 5 others sitting doing nothing. This is LAF
Not only that but you can only move 1 character every 30 seconds. Talk about stupid. Unless you are a whale with your main over 40k, can’t do shyt

My Main Character is not 40k-ish, but only 35k(Solaris), and alternate Characters ranging from 24 to 26k. (F2P btw). What I usually do with Rift 17 is I only move two Characters. One is my Main, and the other one is my 3rd/4th strongest alt Character. I leave my other Characters on standby on the slot near the gate, two in the middle(Main Character and another alt), and kept on moving my Main + 3rd/4th Strongest to the front near the center(only when bosses spawns/depending on which Boss). This way, I can reduce the monsters in order for my other alt Characters to be able to clean them before they reach the gate.

 

It would be good if you have two range Characters positioned near the gate. My current line-up is Solaris, Legatus(Center Position), Shai, Sage(Back position near the gate), Nova(moveable Character in front), and Primrose(near the center, lower position together with sage).

 

You don't need to be a whale, you only need to strategize which character you need to move, depending on the situation.