Cant Saw file and a smaller fine triangle. I am not a fan of crowning files as I cannot see my work progress. I do have the diamond offset crowning for hard to reach spots.
After 14yrs I tried a Diamond knife sharpener , its a 4 sided block which I got from a local german supermarket . It is amazing , it hogs off the bulk of the wear in a few minutes and then you turn it to the next side which gets progressively finer , then I use stew mac diamond crowning files also amazing . I mark the fret tops with black felt pen to highlight progress . Fret dressing now takes about 1/3 the time and much less sweat.
Harbor freight sells 4 sided diamond sharpening blocks. I've used one for a long time. handy for honing chisels, too. It even has a base to hold it for that.
That sounds like the same one .
We may use any of the Stew-Mac diamond files depending on the application or a cant file at times too. Love the diamond stuff in so much as it also works in both directions.
I use a small Grobet triangle file made safe by grinding the corners smooth for most of the heavy work. This is followed by series of small profile diy sanding blocks w/sandpaper applied. I cut pieces of Maple 3" Lx2"Wx1/8"thick) with a 3/32" concavity milled into one of the 3"edges. I spray contact cement on the block and sandpaper is stuck to it and molded into the concave by pressing a 1/16" drillbit into it. Then the sandpaper is pressed against the other side of the block. I have 4 of these blocks with progressively finer abrasive on them.
I have a selection of needle files with various profiles that I like using. otherwise a 2nd cut or fine triangular file, my ATO used to have a fit if we apprentices ever called it that, "It's a ******* three square file for ***** sake!" he would chide us. I do have a set of diamond needle files but I prefer using a standard rat's tail no real reason just preference.