Kero is more expensive because it is more expensive to make.
Power Kero is almost the same as Jet A1 .
Lighting kero ( the blue or pink stuff ) is distilled so that becomes more expensive again.
Then there are distribution costs.
back when every fuel station sold bulk kero it was cheaper than petrol but now (Down here at least ) it is all sold in containers it is a more expensive as you have to pay for the packaging and shipping of the same.
You will need to work out the correct jets.
On most of the old kero gear we had there were 2 carbs, you ran the engine on petrol to warm it up then turned the changeover valve to run on the kero carb.
Much the same as duel fuel LPG cars.