Assuming that your fretboard is already at the correct radius, there is absolutely no reason why you would need a caul or anything else to put the frets in. You don't need a fret bender either. Using your hands (gloves help, by the way), carefully bend your fret wire so that it has a tighter radius than your fret board. Then, cut your frets slightly long. Tap in the frets with a hammer (a brass hammer is traditional to prevent maring but you could use a plastic covered hammer). Begin by taping the ends in - then tap the center and the fret will seat itself nicely, provide the kerf is slightly narrower than the fret tang. I use a little Titebond glue in kerf. If the fret pops up, that means your kerf is oversized and then you might want to use a slightly radiused block to hold the fret(s) in place until the glue sets up. I highly recommend that you buy yourself a radius sanding block (Stewart MacDonald - about 15 bucks) for sanding the frets and for using as a glue caul. Of course, your going to need some files to dress the frets and a nippers to trim them. I highly recommend getting the fretting book that Stew Mac sells.