Pioneer P8MP install, relay? other tips?

Hi, Just got a new Pioneer P8MP head unit. one of the new on the market that has higher power amps right from the unit. (peak is 240 W, Vs the normal 200, but the biggest difference is that if run 'low' power, or what normal units run, it outputs 20W continuous, but in high power it goes 27W (30% more ))

And I’ll like to run it in 60W mode not 40W

like the alpine 9835 Its more recommend to draw the power directly from the battery.however pioneer seems very goofy. It looks like they want 10 amp lines on both the continuous , and on the acc on power line.my concern is that i don't want to overload any circuit that might be drawn from the harness.from my old setup, i took power from the windshield wiper fuse , but it seems like that might not be enough this time.sooo heres what i'm thinking of doing.Run a 10 gage power cable from the battery to inside my car and hook it up to the coninous. (easy enough) but this solves only half my problem.soo to fix the other halfi want to get a small relay (radio shack, single pull single throw)and connect the power in line from the battery, the other side to the acc on in the radio so that both lines will get powered from the battery.heres my question...what do i use to turn the relay on?i know one side goes to ground, easy enough. but what line can i tap from the harness so that when i turn my key power hits the relay and it latches?any help, or ideas as to how i should wire this up.?

Edit added info

was thinking along the same lines that you are about the acc not drawing any power until i saw the radio wiring harness.

on both the acc (yellow) and constant (red) pioneer installed 10 amp fuses, plus the red is split in 2 and goes to 2 separate points into the radio no idea why they did that.but with a fuse on both constant and acc lines would make me think that they both will be drawing power.plus the wiring for the acc + constant is a thicker gage then the wiring for all other connection. not quite 10, maybe 12, but its definitely bigger then all the other linesand it has a big fat almost 10 gage ground coming out of it that needs to be connected to a separate spot that’s not the harness. my old head unit just used the wiring harness ground.

2001 sunfire se 2.2

the red line is just a remote, its not gonna draw alot of current, just enough to switch on the radio. The reason for the fuses is a fail safe system. Incase of a short, it pops there fuse than damaging the vehicles electrical system. But if thats what you wanna do, tie one side to ground like you said and the other to the accessory wire (ignition) and then wire your relay for normally open (NO) so that when the relay is energized, it makes the contact. Radioshack maynot have an automotive 12v relay so try an auto part store or car audio shop if you cant find there