No need to pre-heat. The pedal is low carbon steel, so it will take the weld without any problems. Match your welder heat setting to the thickness of the work. In this case about 3/16" steel should be level 3...and possibly even level 4 would work. Of course you will have to turn up your feed to correspond with the higher temp. If the feed is too slow, it will act like the weld is "skipping", with pauses during the weld. Slow feed also causes the wire to get stuck frequently in the tip, so you have to stop and clear the tip frequently. Fast feed spatters a whole lot, tends to get the wire stuck in the work, and pushes the tip away. So turn the feed up about 50% from where you have been working, and then read it from there to see if you need to adjust a bit.
As you say, work in small lines, building with each subsequent line. For such a small hole it will be relatively short bursts...like 2-4 seconds each. After all the thin metal welding you have done, this thick metal welding is pretty easy in contrast!