Take some advice that another "high numbers" boxer did not take (whom shall remain nameless):

Don't jump straight into more than 5 boxing. Stick with 5 until you get to 80. Micro managing 5 toons takes a while to get used to. Once you are comfortable with just 5, you might not even have the desire to go for more. There's some serious diminishing returns once you go past 5. With 5, you can solo most of the content, and it's not that complicated. With 10, the only thing you can do that you couldn't with 5, is do 10 man raids, and do 2x as much dmg in PvP, while at the same time, limiting the rest of the group, meaning a larger cluster of toons in one place. AV is won by keeping a few people spread out guarding/capping towers. If one person rolls around with all 40 toons in the BG, he will for sure faceroll any horde that comes at him, but some horde will get through, some of your toons will die, and gradually, you will be worn down, forced to either try and rez your downed toons, or abandon them at graveyards. Only you can win, is if you can get to the end boss and zerg him, the zerging is easy, with that much firepower, but getting to him without drawing attention (and believe me, 39 toons /following one, will easily get your main focusfired down, your team fearbombed, etc. I see 5 boxing as the max to do while realistically making a difference, without being overkill. if 5 flameshocks can kill a lot of players alone, 10 is just overkill. MAYBE i could see 10 boxing in AV, but anything more than that is a waste.