Dry Firing an oil burner and Cast Iron Radiator Replacement?

I recently purchased a house in the Catskills region of New York am slowly getting things working again. I just had the service upgraded and now that I have electricity I'm looking to tackle the heat. Currently the house has two zones off of a oil burner (which is also the source of hot water for the house). Zone one is a number of cast iron radiators of which one is missing, and zone two is a number of traditional slant fin copper baseboard heating. My basic questions are as follows.

1) Where can I buy a radiator to replace the one that is missing?
2) Can I replace it with something like slant fin or a "european style radiator" and leave the remaining radiators the same.
3) Because of the fact that there are likely issues in the copper piping (as well as a missing radiator), is it safe/possible to briefly fire the oil burner up (to make sure it works) without having either source water or output valves open? My plan would be to basically add 10 gallons of diesel to the tank then bleed it before starting. The rationale being if the boiler has a serious issue I may replace it with a mini-split heat pump and electric resistance as a backup (so actually dealing with the radiators becomes moot).

Thanks

You can fire it up but for no more than 2 minutes. As far as mixing copper fin with cast iron radiators it usually doesn't work too well the copper fin heats up a lot sooner than the cast iron radiators.

johnjh2o said:

You can fire it up but for no more than 2 minutes. As far as mixing copper fin with cast iron radiators it usually doesn't work too well the copper fin heats up a lot sooner than the cast iron radiators.

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Thanks, that makes a lot of sense. If mixing is out of the question I guess that leaves me with either replacing the missing cast iron radiator or replacing the 6 cast iron radiators with something else.

If I were to replace them all would it make more sense to go with something like a modern panel radiator (like Myson) which would make pluming them simpler or with a baseboard type of approach?