Are you going to be forging it, or grinding it from a bar? What will you be using to heat it for the quench?
Optimal would probably be to use an oven, soak for 10 min. at 1525 F, quench immediately in a medium speed quenching oil. Temper from 375-450 depending on how tough you want the edge, twice for two hours apiece, and then if you want a softer spine, thoroughly heat the spine up past a blue-gray temper, from both sides, with the edge in water. I try to "soak" the blade at the spine tempering heat for a couple of minutes. You can find quidelines for tempering 5160 in books like the SECO-Warwick heat treating guide.
If you forged it before HT, you'll want to normalize it at 1600, 1575, then 1550 after forging. Then, you can sub-critical anneal it three times if you'd like to be able to drill it and grind it easily. That's 1350, air cool to 900 and quench, three times. You may want to add a 1550 normalization after rough grinding.
This is optimal as far as I understand it. I have my own ways, following the temps and theory as best as possible, since I have only a forge for HT just now. I treat 52100 similarly, but with slightly lower temps involved.
As far as I am concerned, and the industry in general I believe, a fully martensite blade with a variable temper, rather than an edge quenched blade with pearlite-ish spine, will perform better for you.
As far as the correct quenching oil, not sure what would be best. Park 50 would probably be overkill, although I've used mine with success on thin 52100 and W2. Perhaps McMaster Carr's 11 second or even 28 second oil would be a good choice. Right now I'm using soybean oil preheated to 130 F for quenching higher alloy steels, works well for me, but not truly ideal.
