Hi GM,

what ever shape you choose, you are best to cut as close as you can to the final shape (1-2 mm or closer without breaking your line.
The danger with routing is that if you strike funky bits of grain, or try to take too much off you may burn the wood, or the bit flutes might catch and cause big tear out.
Good quality carbide bits help
https://www.carbatec.com.au/routing-...2-shanked-bits

i have used the first three on the linked page in my little workshop and they go well, but the rule is cut as close to your line as possible.

or you can go bonkers with it,

https://www.woodworksupplies.com.au/...whiteside.html

these are supposed to be the ducks nuts of flush trim router bits.
You don’t need to go that nuts, a decent straight 2 flute carbide bit with a top mount bearing should be more than adequate, you just need a good well made template to run it against. 3/8” or 1/2” diameter bits are common and easy to get a hold of at a relatively low cost from most specialist tool stores or big box type hardware stores.


But I think for headstocks, most of the forum generally cut then sand/rasp/file to shape. It’s slower, it’s harder work, but mistakes happen at a lot slower speed, so the damage can be mitigated. Routers are unforgiving and busted headstocks are a pain to fix.
Most of mine are either coping saw to rough shape, then rasp, file and sand, sand, sand and then some more sanding.