Advice for fitting sounder

[Rubes]

I’m about to fit a Sounder/GPS (Matrix 27) to my 15 foot tiller steer tinny. Just chasing any hints that people have learnt from previous experiences of fitting their own.

Any advice on where to mount the sounder? Was going to mount it on the side (no console to put it on) – or should I fix a bracket to bring it back into the boat a bit?

Any advice on where to mount the GPS mushroom? Straight behind my seat in the back corner (next to the cleat) or on the side? Or the bow?….

My mate is a bit of a gun at electrics, but any advice for that side of things?

Anything else to add?

Thanks