I didn't say that you are forced to use more than 1 pc, I said that I use just 1 pc: my main DD, an ISS, and a mentee (who is fishing)
There are several ways to get the 15 points per day fast: primeval isle, storm isle, refinery, you can even reset your dual and go to coal mines (if you are so desperate or have a 105 dual already, and with your set i guarantee that you will do all the 15 in less than an hour)
Let's say that you are so anxious that you want the top grade max lvl homunculus asap, with those 15 point per day and using what Nymphadorea said, youll need 530 point aprox, thats 35 days of farming, a little bit more than the old "Exploring the dimension - 30 day" quest, Don't you want to use the power fish, will you farm just 5 item per day? ok, youll need 105 days instead, a little bit more than the old "100-day subjugation operation" quest.
This is not only a pay to win game, this is also a farming game, you will ride the Lexus but it will take you a little bit more than the 10 minutes that usually takes someone to use the credit card.