I just fill the slot with super glue then take a rubber tip hammer and push them in with that and slide the hammer across the fret pushing it in instead of hammering then take an extra radius block and squeeze clamp the fret in (I usually have three frets in before I clamp) let it dry a couple mins, move on and repeat. I find this is cheaper than buying press inserts and all that stuff and with this process I have only had to level the frets once (my first build) other than that the frets stay perfectly level, that is if the board is level to begin with.
Love this build though, its lookin good and I like that ebonizing technique I will have to try it sometime.