100 gal will be heavy. 60 gallon + carryall frame is a load for an old 8N. Think about all the features you would like to have and build your own. I have a short boom for gravel areas, hand wand for around buildings and poles, Wide broadcast nozzle for yard and big areas, and just added a field edge 06 half nozzle to spray about 3 ft around edges of fields for touch up work. Here is my build. https://talk.newagtalk.com/forums/thread-view.asp?tid=464550 | 
A spot sprayer with a boom less nozzle?
