12 String Tuning

I have it in D standard tuning and intend to keep it there. If I need to play in E standard, I just put a capo on the second fret.

I just feel like the amount of tension on the neck from 12 strings in E standard is too much for the good of the guitar. And it doesn't hurt that if I eschew the capo, I can sing songs down a full step! 

When I rebuilt the 2000 Seagull S12+ I built in my own (smaller) version of the Bridge Doctor to keep the bridge and top from tipping. That's half the problem with a 12 string. Hopefully that's enough to keep it from having a problem with standard E tuning.

Or build them a little better to withstand the forces of E tuning.  Building in the Bridge Doctor (like Breedlove) would help.

This thread is the first time I've heard standard tuning referred to as "E standard". I would assume you're naming it after the note that the first or possibly the 6th string is tuned to.   I've always just called this "standard tuning". 
When I had a 12-string, it was tuned a whole tone low to DGCFAD with a Paige capo on the second fret. This capo came off only for a string change. I didn't use another capo on the 12-string, simply because of the tuning problems the capo introduced.

When I bought my first 12-string (the Giannini Craviola), a luthier told me "Rule Number 1 - tune it a step lower, and put a capo on the second fret". And so I do...I want them to last a long time...

oooo Bb,,,,did he use a heavier string?

Lead Belly also tuned way low and his bass course was two octaves apart.