Would 60 degree cones work well for a .45 suppressor, or would K baffles be a better choice?
I see where I can buy TI or SS cones, and I have built K baffles for my .22 suppressor too.
Just want to know which way I should go before I start my plans.

If you have the ability, I 'd do them similar to the Rugged Obsidian. Hybrid of cone and radial.

They both work well.  K's can have lower back pressure.   However the built-in spacing of K's limits how many you can stuff into a given length. Some long snout radials also need a certain minimum spacing. So if you are going a full length 1.375" X 8" it really doesn't matter much.  If you are designing a short K (Kurtz) suppressor then cones or radials or Rusty's design (snout, cone, face) will give you more spacing options.

As far as back pressure, if you reload with fast powders like Titegroup that helps reduce unburned grains blowing back into your face on pistols.

The 1.372 od RSC is .520 tall. It works very well on both subs and supers with the DHC cip. The od can be turned down to 1.255 od and be very effective.