Ed,
I have found a local source for cryo treating. If I triple quench and triple temper 5160 and 52100, where in the process do I insert cryo treatment?

After the third tempering cycle cryo the blade(s), THEN....... run them through another tempering cycle, at 25 degrees higher than your previous tempering cycles.
In other words.....Temper three times at 350F for 5160, and 375F for 52100, then cryo, the retemper 5160 (once) at 375F, and 52100 at 400F. This will give the correct working hardness for the steels, assuming that the forging and everything else when off without any hitches. Let us know how it works for you!

Another semi related question. Do those programable ovens offered by knife supply outlets make Tempering any easier, (more accurate or set and walk away) or are they for doing heattreating on stainless etc.?

Those oven can be used for tempering just about anything, as long as the chosen model is within the temp ranges you need. I personally don't use anything that needs a very high heat for tempering, and with economy in mind, just use the kitchen oven. Maybe someday I'll get one, but for now the cost doesn't justify one for me.