I'm sorry I am not posting too often, but with two small children my JBL hobby only gets so much time...
I just wanted to let you know I have finally hooked up the 2435 + 100x100 waveguide (the 338785-002, or PT-H1010HF). I have had this combination boxed in my garage for years. I have done much effort to get the right horns and then I had 2 children (or, my wife did actually) and then, nothing.
I have hooked it up to the existing crossover that my 2420 + 2344A combination has been playing on the past few years.
Out of the box it sounds fine, but the drivers have been in my garage for the last few years so they probably get better (or different) when they come up to room temperature and everything has setteled down a bit.
I'll try to see how they develop over the next days. I know there are threads about this driver / horn combi, I was following them a few years ago and decided to buy this combination. So now I'll be able to hear them for myself.