Stefan G has some good videos on using the Deckel knock off.
You will want a few diamond wheels to go with it. Buy the carbide D bit blanks already having the ends split ground.
There is one thing, that isn't apparent, worth noting. The top rotating pivot can be moved past the zero stop by pulling out a small pin. Handy for some grinding angles.
It takes some time to figure out all the adjustments.
I bought the model with 5C collets.
Grinding an endmill to center cut may be possible but I haven't mastered it. 2, 3 or 4 flute end mills can be sharpened but more flutes don't work.
I will use a Dremel to take out the center when required.
It is possible to grind the flutes. There is a good video for that. The trick involves using a small spacer to shift the bit. I'll probably get blasted for this but: I'll use a diamond wheel on HSS if that's what I have. It will degrade the wheel over time. Wheels are fairly cheap but my Shars takes 1 1/4" bore and they are not as common as others.