To be your own lawyer ,See what local laws have on the books ,any cases that you can find that show a winning verdict could be helpful for a good end to the barking borderline.The privacy does seem to be your capturing issue though ,how much will the law allow for court is apart of why lawyers keep in business and you out of being in one.I would setup a cheap harbor freight outdoor security camera ,non expensive black and white and does capture video and audio desently within 40 ft ,Ive used one in the past and you can capture this via a VHS machine,I did say not expensive.I think my whole cost was less than $90. The audio was ok ,video was ok ,you just need to show you at your home and the noise that the neighbors dogs invade upon that home.The audio is picked up by the camera piece ,it came with 50ft of transmitting line and is sensative enoug to pickup twilight hrs nut doest like direct sun ,most cameras do not..The night capture wasnt there but you can set out a light possible next to your fence to show a designated part of your yard identifing it as your yard only ,a drawing of perimeter for court reasons will allow an overview of property at that time .The early morning hours would be good as the sun comes up , this showing 5am til 9 am. .You then could capture 8pm til 12 pm .The 4 hrs being how long the VHS tape can record.You can condense this for court purposes with editing ,around 10 minutes of review at his bench if it gets to that stage. I Dont suggest the extreme but some people might do this and purchase a very good recording device ,buy an even better speaker system ,record their dogs and return their own nuissance back too their ears x 4 at 4am in the morning .This would make the local news but you know that only feeds these people .