My advice: Do all the FILE work before heat treating, and get it to the exact shape you want. Before HT I wouldnt worry at all about finish, but at least get it smooth. HT will give you a good layer of oxide scale to sand off so its pointless trying to get a finish before the HT. After HT it will be difficult of not impossible to file, depending on the hardness, and thats why I say get it as close to final shape as possible.
Another tip, as I have been advised on this forum... dont grind the final bevel before HT as the very thin edge will respond very differently to the rest of the knife.
Good luck. Nice looking knife shape there.
Lang