You will still need to pay the individual casting cost for each Commander, and Commander damage done to other players is tracked per card , not as a total
Should you have a reliable way to give them haste, this creature becomes even more frustratingly deadly
For trophy cards, vintage holos, or any card you plan to sell for top dollar, PSAs wider market appeal will usually net you the highest price
Even one extra energy can make a difference
For tackling the first 3 it helps to use a brute force approach of ridiculous numbers of projection images, exposure time, and some techniques taken from for instance my experience scanning industrial batteries
Id swap over some big mana sorceries for instant speed removal like Pongify or Rapid Hybridization and include a Ral, Storm Conduit to start shooting down bodies and opponents more consistently