Oil Fired Indirect to Gas

Hello-

I currently have a Weil-McClain Gold GO-7 steam oil boiler with indirect hot water tank.

I'm converting to gas.  Oil companies are just dishonest.  Even if it breaks even, at least I trust the gas meter.  I already have a 250 gas line that powers just a kitchen range.

I can't figure out the best, most cost efficient replacement option.

examples:
seperate gas fired hot water heater
hybrid hot water heater
new gas fired steam boiler
retrofit existing boiler from oil to gas gun (remove indirect??).

any ideas, how to calculate benefit-cost would be highly appreciated.