These images might make good test ones to show yourself the effect that each filter has. Assuming you have a full set of filters, try printing one of these images with each filter from 00 to 4, all 1/2s as well. Also, do them all at the same exposure time and then do several of them at times based on what you see in the first run. This should give you a good idea of how the filters affect the image. Basically, a lower number filter will give you a lower contrast and a higher number will give you more contrast. I don't think you should try split grade printing until you know how the filters work. There's also a great explanation on the info sheet that comes with Ilford papers.