I just received a PIF of a Sensor Excel razor. What I had in mind for this razor was to be a finisher razor and travel razor. Right now, I use a Gillette Guard for those duties, but just wanted to try something else. Since this will not be in my daily rotation, I don't need a Gillette cartridge, but just something cheap that will last a couple of days and give a decent shave. Any suggestions as to which cartridges to try?