When you work on the 8 inch loom, it's okay to just weave one band at a time, as the warping bar doesn't flop around.
But, on the 16 inch loom, you do need to either warp up 2 bands, or secure the other end of the warping bar with a cord so it will stay perfectly horizontal.
I tried weaving 3 bands at once on the 16 inch loom, and didn't like it, as the center knobs on the shedding device got in the way.
Two bands are just great though.
AND.... if you want to weave longer bands, and have either a 12 inch or 16 inch Mirrix loom then the loom extenders will be your friend :)
I use a crochet hook and a weaving stick to make the heddling process go quick like a bunny.
Here's the video tutorial:
Start by placing a piece of cardboard between the layers at the front of the loom and the back so you can't see the warp strands at the back of the loom.
Pull the heddle rod back so it's about half way along the warp strands.
There's a gap between the strands that have gone in front of the warping bar and behind it.
Slip your fingers into the gap and scoot them up to the shedding device.
Slide a shed stick into the gap.
Voila! (which is how 'walla' is really spelled :) )
You have shed one ready to heddle!
Catch the other end of the heddle loop and place both loops on the heddle rod.
Go slowly, and be sure that both ends of the heddle loop stay politely on the heddle rod.
Repeat the heddling process on the second set of warp strands for your other band.
Take the warp strand from the back to the right of the one in front, and onto the hook,
take the hook over the front strand, and pick up the next strand and carry on across.
Check your heddles carefully to make sure that they are opening the sheds properly.
Ahhhhh! a warped loom is a thing of beauty!
Open the first shed, and insert a craft stick, then open the second shed and insert another craft stick.
Squish the warp strands together to establish the width of your band.
Change sheds, and weave the next row.
Pull up firmly on the tail end and weave it through the same shed.
Repeat several times until the tail end is woven in, and the band is established.
Next video: The fun part! Wheeeeeee.... weaving......