Hi Y'all,
Several years ago I made tie-dye shirts for some of my extended family. They were a big hit (although rather poor looking, since I had no clue what I was doing and there was no miraculous interweb to help me

) and so two years ago we decided to make some more as a group. I loosely followed the instructions from Tom&Martine's Tie-Dye 101 DVD. Again, the shirts were a big hit. So now we're doing it again, but this time everyone in the whole family wants a piece of the action!! We are looking at approximately 30 shirts, some of them in plus sizes, and a couple of longer, cover-up style tees.
Here are my questions:
How much dye will we need? I ordered an 8oz jar of each the primaries, and 2oz of mixing red, cobalt blue, grape, and golden yellow.
We will be dyeing outdoors, in the shade, but in SC in mid-July. Expecting at least 95-100 degree temps. Will this affect the dye? It will take hours for everyone to make their shirt, so I'm worried about dye demise after it is mixed. Is this a possibility?
If using bottled water, is distilled better than "filtered"? We are dyeing at a house with well water, so I know the mineral content is high and I neglected to order softener from Pro.

For time's sake should I mix the dyes the night before, as long as I store them in a cooler? Should I soda soak the night before, and for how long? We will dye the shirts wet, as I found that easier & more effective last time.
Suggestions?
I did look elsewhere on the forum for some of this stuff but I'm still a bit confused. Thanks in advance!
Lilah