So I ordered an antenna, A99 with the ground plane kit. So this will be a two parted question.

First, does the ground plane kit mitigate interference on adjacent devices, or is it completely useless? I bought it because it came at a good price as a package deal. I'm not committed either way with the GPK. If it will keep me off my neighbors electronics, I'll install it.

Secondly, I have an idea about mounting I'd like to run by those with much more experience:
Would it be at all advisable to attempt a home brew of something like this
http://www.rohnnet.com/rohn-nppk-mount
made from hardware store tubing? Weld or solder all the joints, weld or stainless steel bolt an attachment at the peak to hold the mast.

Thanks in advance. It's been fun reading through the forum here after getting back into radios. And I also ordered the ARRL Technician study guide.