I used an FN for about 20 years before upgrading my boring equipment. And I still have it. I never bored on the fast feed/speed unless I was sleeving and needed lots of material gone. But you generate lots of heat so you have to let the block cool down before a final cut on slow/slow. If you bore on anything other than slow, you'll get almost .001" taper in the bottom from the heat generated at the tip. The narrower the cutter face angle, the better the finish but it requires frequent sharpening.
There are aftermarket holders available that use a triangle shaped insert. It's what I used for a long time. Finish is not as good as the oe carbides but if honing after it matters not. HOWEVER, you need to re-calibrate your mic as this tooling will read differently from the original, as it puts the cutter tip off center as compared to the oe cutter.