You can make slips by putting silicon carbide wet sand paper on a shaped piece of wood. I also take pieces of pine cut with specific tools and apply abrasive compound to touch up the insides of the profiles. You can get a perfect match for V tools that way.

Yes, I’d seen Mary May’s guide and that’s what I was following for mine, though Peter Follansbee has commented that if you let the root get too rounded, it doesn’t work quite so well for this sort of carving:
https://pfollansbee.wordpress.com/2010/06/21/carving-gouges/

I tend to grind the bevels on the sides first, then spend time rolling the root around like it was a very very tiny gouge; and then the same approach on the stones.
I did need to get a new slipstone though, the ones I have are quite short (like 2 inches or so) and that’s very useful for some of the work, but they’re also quite fine (like an Arkansaw stone) so I’ve a medium grit one that’s a bit longer on the way from fleabay (just a king waterstone multiform thingy at 1000grit, nothing fancy). The diamond plate slipstone I have sounded great but the diamond coating was cheaply put on and the gouges have been carving small slivers of it off until there’s less diamond than there is plate.

Here are some examples if you haven’t seen them:
https://www.finewoodworking.com/2009/10/29/sharpening-the-v-tool

https://www.marymaycarving.com/blog/2011/10/04/sharpening-a-v-chisel-or-parting-tool/

A square end to the tool is a good default but there are cases for wings leading and trailing for specific jobs. That is where having more than one of a particular sweep is handy.