I will second Bulldogma's input. You really need to use dry hatching methods with SFH. While my incubator is not the best, Farm Innovations 4200, my results have greatly improved with dry hatching and subsequent jacking up the humidity to the 55-60% range at lock down.
I also find I have better hatches with a dry incubation but last summer when it was really dry for a time and I didn't have any moisture in the incubator, I found that the SFH eggs lost too much moisture because humidity got way to low in the incubator and I lost some that way as well. Humidity was down to like 15% or less and the lighter color eggs like my SFH and my rhodebars evaporated faster than the darker shells. Best bet is to weigh eggs at beginning and periodically though out to be sure you are on the right track with weight loss.