With high humidity dry incubation can be a very good idea. A dehumidifier wouldn't be needed. But, if you're comfortable with adding water and you've had good hatches that way, you could go ahead and do the way you wanted.
right now our humdity is running 75%-100% in the house . i have been doing dry hatches for past 2 months. with it dry my humdity runs 40-55% in my still air incubator. i dont use a humidifier. have actually had better hatches this way. i only have to use a 1/4 cup of water or less for lockdown which is good no sponages at all only one small well filled.
so far our RH has been 70% + I live 5-6 miles from the coast I have marsh all around me I moved inland for a while but I shed like a snake with out the humidity I run 1 of my vents open all hatch the chickens I hatch have been doing almost as good as the quail and chukars I hatch I just hatched 20 chukars out of starting with 24 I had 22 at lockdown and got 20 to hatch the last coupla serama hatches I have had were 4 out of 6 eggs and 5 out of 6 eggs