Welding Co2 Vertical. If you plan on welding thinner material such as sheet metal stick welding is not the best choice. Also if a mig welder is equipped with inductance setting control a higher inductance setting works better for me with co2 gas.
Use an AWS classification ER70S-3 for all purpose economical welding. You can use a triple-mix for stainless steels Helium Argon CO2. Automatic Vert Welder AVW-Multi pass are m ultiple pass flux-cored wire welding machines.
Sure there are other ways of making a good looking vertical uphill weld but for ensuring penetration as well as making a good looking uniform weld the upside down V is a very good way to go.
For steel there are two common wire types. With MIG welding you can just pull the trigger and start welding your project. Voltage and wire speed are usually a good bit lower than for flat and horizontal if you are using a mig welding chart you can usually just select one or two thicknesses under as a good starting point. 85 Argon and 15 CO2.