If you ground a radius into the cutting face of your cutter, parallel to the bit's long axis, and about the same radius size as you have on its cutting corner, you would have what I had mentioned.
I tried to find the round insert and holder you pictured above. I found the inserts. Rather pricey, but considering they offer several times the 3 cutting orientations to which I am accustomed with the triangle shaped inserts, the price seems justified. However, I could not find a holder for them anywhere, and I looked for quite a while using Enco, Amazon, MSC, and eventually just Google. Nada.
Rather strange none of those vendors listed the holder on the same page as their round cutter. Most vendors try to get you to look at "what others purchased along with this product" to get more items in your cart. But I admit most vendor search engines are completely abysmal. Even after finding the technical code name for this style of round insert, sites like Enco could not find anything using that name. Without someone's part number for the actual holder, I would probably have to dig through a paper catalog to find it. Aren't computers supposed to make life easier?? lol
Thanks!