Sorry dude, I was uhhh, feeling good last night I guess.
+4 Will help your powerband in the low rpms the most, and mid second, and wont make a whole lot of difference on the top end.
If you have a lot of compression and or timing, it can have a negative effect on the top end power, but makes it even stronger out of the hole.
But just doing +4 you will see a nice gain from the bottom up, without noticing any loss on the top end.
My point was to just do it, and if you don't like it, put it back....
I ran +5 on my stock stroke and loved it. The plates are only 35 bucks and its pretty easy to change, play around and see what you like. I wouldn't go over +5 though, depending on your compression and what fuel you're running, etc.
Install the timing plate and set to desired advance, and impact the flywheel nut back on but DONT put any blue threadlocker.
When you are sure you're happy, remove the flywheel nut and use some BLUE threadlocker, and impact back on and call it good.
My .02