I agree with Vinnie. The more damage you do, it adds to your contribution to the battle, therefore you will always make slightly more for end plunder. Whether the extra payout is worth the mith cost? I'm not sure because mith cost is determined by your strength. For my alt I was able to purchase mith for 348m but on this guy it was 480m. Hope this helps!
Mith is a rare commodity unless you do do system wars quite often. I'd refrain from using it in ebs unless you really need to.
Thx for answer. Next ?: If I start an EB then wait til other clan members are active can I leave or will it forfeit the EB?
With your size if they are the same size as you, it's possible I believe, my main has been hit by a 4m CS Hansel, and lost 500m, so I think so
It depends on what you are planning to do. For example I use the diamondiferous when atking the eb, and the abyssal blade to spy on people. Just look at the stats each one gives you and compare.