What is the recommended GPS/Chartplotter/Fishfinder & mounting procedure for kayaks & canoes?
Depends a lot on your boat, the specific GPS/Fish finder model, etc.
With the new fishing SOT kayaks, the designs are build to accept GPS mounting hardware and will have a portal for the transducer. With the older kayaks and canoes, you will be required to jerry rig more.
Youtube is your friend. Go there and search for your particular boat and how to rig it for the GPS/fishfinder. You may also have to do a search for the specific GPS model as well. With youtube, you’ll find multiple videos that will relate to you boat and/or GPS.