Anyone have experience resealing tank?

[nhbsab]

I recently bought a 200dd. I making a drop off shelf out of glass. I cut out the corner overflows and am putting in a 35" narrow overflow box.
I could use some advice or help with sealing the drop off. Please let me know as I am ordering the glass now.
Thanks
Steve

 

[nitr8]

I built my sump and refugium. Built a display too but someone backed into it while it was outside water testing. Still didnt leak but chipped the glass on one of the corners.

 

[TURKLET0N]

I just resealed my 150 a few weeks ago. I only did the inside though