The Tamar is pretty good, sheltered but can get windy. Once above Weir Quay there is little opportunity to get off the water.
Launch at either;
Weir Quay, Devon side, quiet, narrow lanes to access.
Jubilee Slip, Saltash, Cornwall side, busy, easy access below the Tamar Bridge,
I would normally offer to show to team up & you around but my current car doesn't have a tow bar yet. Plus I am currently building a Sev with 1387 Squadron Air Cadets and my craft hover hours are 0! (sadly I haven't used it since before Covid :'( )
I will PM you my phone number, I am almost always available to talk hover but evenings are best.