Ultimate touring but funky build. Input required.

Hi everyone, I'm a new member with 27 years riding and touring experience . I have a number of bikes but have just added a ropey 2017 grom to the collection. The plan:
Completely refurbish the bike so it's seriously beautiful/custom.
Tune the bike as much as possible while still maintaining a high level of reliability.
As it will be used for channel hop touring the Normandy area of france, I want to preserve as much fuel economy as possible when ridden gently.
Ideally cruising at 60mph would be nice but I accept that may not be viable.
First things on the agenda are:
Bar risers
Wider bars
Panels repainted
Wheels dipped and powder coated
Graphics kit
Exhaust, I want a high one, maybe a twin can I have recommendations.
Big bore kit- help which one?
ECU programming, where do I start!?
Any recommendations greatly appreciated and I post pictures and results of each item added.