Yay! You did decide to put pictures up with this! It looks great so far! When I rebuilt my 25 gallon tank, I had to tear it back down like that. A few helpful hints I learned along the way.
1. A helper to position and hold things is indispensable. Even if all they do it keep it square while the next piece goes on, so worth while.
2. Before siliconing, put all the hold it together bits of tape on all the bits of glass. This is probably common sense, but makes it easy to get it all together. When I did my taping, I did some from the bottom piece onto the side pieces as well, to help keep it all centered while it dried. It may have been redundant, but it made it go nice and smoothly.
3. Wet paper towels. Seriously. 3 of them on a plate ready to go. You WILL get all sticky and you don't want to leave finger prints in the middle of your front pane.
4. Straight seams can be achieved without tape. If you think you can hold a steady, even, quick pressure, then it's not worth doing, and a whole lot more effort to take apart.
5. Pick which pieces you want to be front and back. Theoretically, there should be no scratches on them at this point. Check anyway, mark with a sharpie. The last thing you want to do is guess when it comes to putting it together.
These all seem like stupid, common sense things. Until you have silicone all over your elbow and keep sticking it on your panes of glass and cursing.