First off, good to see everyone. I've been coming to this forum to read for a couple months now, but just recently started to build my own saber.

I have an old Dark Initiate Ultrasaber that my brother bought, I..."reclaimed" and cannibalized after he left the country, but I'm not looking to just purchase a saber and call myself a Jedi. Imma make a thing.
So my questions.

1) Is there any way I could/should resize the internal diameter of the now-empty hilt to give myself more room to work with?

2) Batteries. What kind do I need? Where can I find them? What voltage, wattage, diameter, and the rest of the fancy jargon for this. (I've looked, but haven't been able to find the thread with this. I would love a link if I just missed it.)
I've considered making in-hilt charging, but sense I plan on an internal structure to carry all of the...everything, I feel that might be a bad idea, and I should stick with removable batteries.

3) I'm a personal fan of Makototsai's style, and in my humble opinion consider his blade method to be the best.
But I don't want a standard color, I'm going with Arctic blue. They don't make Arctic blue LEDs, so how can I make my saber that color? My current plan is to put two strings into the blade, one white and one blue, or possibly two blue and one white. (so three strings.)
But would it be better to place a white LED on a blue LED (same string) to make the desired color? Has anyone ever experimented with this?

4) Whats the best way to display a crystal? Just a single LED at the base? Perhaps a 3mm put into a small hole I've made in the base?

5) Lets talk balance. Very important in a properly made weapon, and my group focuses on the combat side of things. Should I even bother, or would that be putting wayy too much thought into this? On that note, how would I counterbalance the hilts weight? Blade length?

I have searched for all these questions, I haven't found any answers to them. Perhaps I'm not looking hard enough, and if so, I'm sorry. =/