I wouldn't bother trochoidal milling in grey iron. It's too easy to cut.
Here's the secret with abrasive materials.
Each time an endmill's tooth enters the cut, it accrues "mileage" - It has to travel a specified distance each time it enters the cut. Mileage = wear. If your part is 1" long, and your hypothetical 1-flute endmill is fed at .005" per rev, then that means it will take 200 revolutions - or cuts - for the endmill to feed all the way across your 1" long part, and remove all that material.
If you increase your feed to .007" per tooth, then it only takes 143 revolutions of the endmill. You just saved 67 revolutions/miles of wear on your tool, meaning you gained 33% tool life.
So, there's the lesson on feed...
Now, let's look at cutting width.
If you can do with with only 1 width pass, then good. If you choose a trochoidal-milling strategy, then let's say you have to take 5 width passes, instead of 1.
What's going to happen to those cutting edges? They accrue 5 times the wear....
HSM / Trochoidal milling works well, when you want longer cutting lengths to eliminate Z-depth passes. It works well when the material is tough, hard, or whatever, when a wider width-pass would prevent cutting of your profile at full depth. If your material is fairly easy to cut, then all HSM will do is add cycle time.
My advise - Buy a good endmill designed for bulk material removal, and cut it all away in one width pass. Leaving stock for finishing is a good idea.
I used to sell Niagara, but these would be good tools for your job, as well as a good resource for learning.
Roughing Endmills - Niagara Stabilizer 2.0
https://niagaracutter.com/search?listings=1&page=1&category=End Mill>High Performance>Stabilizer 2.0
HSM / Finishing Endmills - I would suggest a 7 flute for strictly finishing
Niagara Cutter