I generally get a reply in two weeks or less. One thing Joe regularly writes about is their small staff, so if you sent something and didn't get a response I'd try again.
A lot of inside connections relate parts of the model railroad world. They make quite a difference in getting heard. BTW, if 3 of the same queries don't get a response, I figure none will.
Writing articles is no way to get satisfaction. Instead of writing up how to kitbash, rebuild, modify, and/or repaint equipment/structures, better to do them to sell on eBay or the forums. At least some other people will actually use the efforts you exert, plus the money is better.