If what you are cutting feels like you are cutting plastic, it's too dry, and you've missed the best temper. When I have rawhide that gets this way, I will dip it in warm to hot water, until it starts to soften up, not soaked, and shake off the excess water, and into the humidifier. I use a 14" Tupperware pie keeper. Have two, for stuff that is made up, and ready to braid with, and stuff that is getting prepped. I keep paper towels in the bottom, and put a few over the rawhide, to keep the moisture from condensing on the string in any one place. Plus, the dry paper towels will absorb excess moisture from the string. I check it - if the towels are damp feeling, and the string is too damp, I will change out to more dry towels. I lay the damp ones on the bench, and use them later for other things, or, if they are dry and I need to change the towels again, I switch them back in. Will do this until the strips are where I need them to cut, bevel, etc.
Another suggestion on blades is to use a permanent marker and mark the cutting edge end to end with the marker. As you pull your string, you can see where the unused area of the blade remains, and can move it up/down to get full use of it.