Besides, 5 litres takes up a fair bit of one pannier.
Don't sweat on getting a high octane fuel. If you arrive at a servo that only has regular, use it- the STs can handle it (I have only ever used it in my three STs, including the ST11).
And stop worrying! Load the bike up with all you have to carry, fill the tank and tummy and go have fun. After 300 kays you'll both need a drink, so fill the tank again and grab something for yourself.
And take some photos to illustrate your ride report, or the Mods will be cross!!
