I would not heat it up. Just use campden tablets 1 per gallon of cider you are going to use. I believe that if you heat it you will cause a waxy haze that will not clear. The cider mill I went to uses flash pasturizing now because it became state law recently. I reallywanted to get non-pasturized so consider yourself lucky!
I started a cyser last month using the following recipe.
3 1/2 gallons pasturized cider from the mill
16 pounds of honey (approximately 1 1/2 gallons)
5 cinnamon sticks (probably way too much but the SWMBO like cinnamon)
1 packet EC-1118 yeast
5 campden tablets
Pectic enzyme (I think instructions called for 1 tsp per gallon)
I put the cider, honey, cinnamon, pectic enzyme and campden tablets in a carboy and shook it till the campden tablets dissolved. Waited 24 hours and then pitched the yeast. The airlock was bubbling nicely 8 hours later. It smells the best out of all the ferments I have going.