My models always came out looking like crap, especially when ironing was turned on. As it turns out, the standard flow rate of 10-15% which is set for PLA is way too low (at least for me). So I created an initial set of 6 pieces for proper testing of the best flow rate for PLA. I then extended it with a second plate with different speed settings. 

This print profile provides:

Plate 1:  A quick ironing / flow rate tester. It has a total of 6 different plates with different settings applied. It varies ironing flow rate from 10% to 60% while keeping a fixed ironing line spacing of 0.1mm. You print all 6 of them or just the ones you're interested in. I would suggest to print at least the first 4 to see the difference in top surface quality. 

Number at the top: Flow rate, Number at the bottom: line spacing
 

Plate 2: Different ironing speed settings from 10-100mm/s. This takes the sweet spot of 30% flow rate and applies different speed settings, which also have an impact. 

Number at the top: Flow rate, Number at the bottom: speed

I created this tester as some of the online models did not work properly or provided test areas that were too small to really see the difference.