I have made two of these kites and they both function flawlessly. I was flying them on a Saturday evening with very little wind.
One change I implemented was reinforcing the spreaders on both kites, since the one on the orange kite broke from a previous crash and needed repair.
The kite that was made the other day (seen in the bottom left corner of the picture) was made out of a red and white striped plastic tablecloth. The tails are both three 5' streamers bundled together.
While store bought kites were having trouble getting off the ground, both Deltas were up in the air in no time and climbed very high.
The red and white Delta reached over 300 feet in the picture. The orange one had a shorter line and hovered motionlessly at 190 feet. Both kites flew steadily for an hour and a half until the sun set and the wind died down.
As mentioned earlier, there's more kite-making on this site than you can poke a stick at :-)
Want to know the most convenient way of using it all?
The Big MBK E-book Bundle is a collection of downloads—printable PDF files which provide step-by-step instructions for many kites large and small.
Every kite in every MBK series.