Playing 3 way is mostly just to start or continue a game with weak villains. How long you have to play 3 way is just a factor of site and how long games take to start.
That said once you are 3 way you need to get reads on villains as fast as you can. Playing 8 tables in this situation is not good. I want to know how my villains play post flop, their aggression and what ranges they play from each position. Do they cold call in the small blind, 3bet from the BB HU etc.?
On the positive side you get to play a lot of hands and can quickly assess there post flop plays. The game should become very aggressive as it is almost always HU and any pair is a good hand. C/R will be wide and any player playing fit/fold will be a target to play a lot of hands. Steal wide, once you have a feel for the post flop play of your villains your stealing range is going to go to 65%, if they are tough post flop then it is time to get a new table unless more will be joining quickly and you have position on incoming players.
If you playing a lot of HU or 3 way table starting, you gain two ways you will get position on more rec. players and your steal/blind vs blind play will greatly improve. Table starting is an important ability in the long run. Rake is high so find a good table or leave and try to rejoin if table improves or start a new one.
Also, don't play at higher stakes than your regular game. You don't want to run into a reg and lose a chunk of your roll. Taking shots at higher stakes is best done with full tables, and even FR can be good to dampen variance when playing higher. 100BB loss is 200BB win to make back up at .5/1 to 1/2 or 2/4.