AWhat is a royal icing u recommend. I am using the usual Wilton and it seems to not be setting up. I am used to doing cakes in Arkansas and am now in Ft worth Tx area. Any suggestions

The humidity in TX has been up (at least in the Austin area) but none the less.....add more powdered sugar, get it nice and firm but still workable, 

AI will try that and increase drying time.