Hopefully Ivanising will sort your low rpm issues.
When I got mine, new in 2004, I found it would not run sweet at low rpm small throttle openings. Like running through a village or town in 6th at 30mph. It had horrible nasty surging, nor did it pick up that great when you snapped the throttle open on exiting said village or town.
The carbs as standard are set up to pass emission standards. An Ivans kit gets em set up to their sweetest optimum.
Mike did mine in 2005.
So I ended up going through villages and towns in 4th.
Ivanising fixes all that, plus gives you a wee bit more go everywhere.
Yeah I can easy spend 50,60 quid on fuel in a day heading off hill walking. That's in the car. Fuel is some price, it's crazy.
Ignition timing is a simple concept -
http://www.howstuffworks.com/ignition-system1.htm And now it's all electronic, instead of the old spring loaded distributors.
95 RON is just the ticket, 98RON is for higher compression engines, they need it, the Fazer doesnae.