Will a larger one tick over a lot nicer on a fire due to more iron?
To be used directly in a fire and not suspended over.
I have a couple from Ronnie and they are brilliant. First thing you need to get some good advice on how to use these things the book you want is called something like outback cooking with camp ovens by one of my heroes Jack Absalom. The man was a proper bushman long before all these new kids. Top book, you should be able to get it off ebay from OZ for not a lot of money.
Camp ovens do not go in the fire. You can suspend them over a fire for boiling and that sort of thing but the way to cook in them is as follows.
You can put them on a fire briefly to heat them up a bit but that is usually unnecessary.
Make your fire, Oil your oven, (they should alway alway have a patina of oil on them.) Somewhere near by dig a shallow pit for the oven 3" or so deep. Place hot coals into the pit and put the oven on top of the coals. Legs or no legs doesn't really matter. You need to let it get up to heat - trial and error I am afraid although there is a paper test which I can tell you about if your interested. Once you're happy the oven is hot place whatever you're cooking into the oven, place the lid on and put a layer of hot coals on top of the lid (that's why the big ones have rims. Now assuming you have not overdone the heating you can go about your business and let the oven get on with it. The cast iron gets hot uniformily so you get the oven effect the coals will get cooler so you're unlikely to burn you food. You will need a pot lid lifter - I usually make one out of something green and then toss it in the fire at the end of the camp. My mate and I cooked for 10 using my two weekend just gone, soda bread, fruit damper, smokey beef cassarole and seasoned chicken
If I can help any further just get in touch -
All the best and good luck
Stephen
Ronnies big one with legs will do six meals easy