david,
There are 3 types of transfer. At the lowest voltage settings it will be short circuit. This sounds like a pop,pop,pop, a little like bacon and runs best with 100% co2. This is best suited for thinner material. One of the main issues with this is trouble with side wall fusion. Additionally, most codes don't recognize this as a prequalified process.
Next is globular, this is when your wire is transfered by droplets that are slightly larger in diameter than the wire. Deposited weld metal has slightly better characteristics than short circuit.
Last is spray. For code work this is the preferred process. You need a minimum of roughly 80% argon. The transfer is in the form of fine droplets that are smaller than the wire diameter. This runs at higher voltage. for .035" you will want a minimum of 28 volts and 200 amps. This is from one manufactures data sheet, yours may vary.
It would be best to get a copy of the data sheet from the manufacture of the wire you are using. You can spray your handrail, but you might be able to get approval for using short circuit, less chance of burn through.