ESAB coreshield 8
http://products.esabna.com/EN/home/filler_metals_catalog/filler_metals_product_detail/q/display_id.id4367f2a9663534.21346743/category_id.796/path.filler_metals_cored_wire_carbon_low_alloy_steel_selfshielded_flux_core_coreshield_8_71t8It takes a little getting use to but, by the end of your first roll you'll have it down. I would look into a CV adapter for your 250 it will be worth the money.
Don't give up on the wire, I bought a roll of .072 and ran a few pounds. I thought it was JUNK!!! So I put it back in the oven, I tried it a few weeks later, I was still not very impressed, Then I had some down time and was determined that I was going to use it (at least the rest of the roll). Now I swear by it, if ESAB made a CS-8 t-shirt I'd wear one every day :) Some folks will tell you that self shielding wire is junk, but its like the vantages, if you take the time to learn it there ain't a whole lot that can stand in your way. You might try 1/16 for all position work. I still use the .072 (cause thats what my consumables/drive rolls are) but I would think that the 1/16 would be a little easier for out of position and thinner material.
PS: Try some NS-3M. You'll never buy jetrod again :)
And don't forget to swap your leads to DC-