Bart, if the grafts are taking off the cool weather should just stall them for a bit. I did a bunch of grafts in this cool spell and they are all stalled to varying degrees at varying phases.
Its not looking real good for peach grafts in the next week or so. I would wait until at least mid-60's highs. For apples and plums they callous reasonably well at lower temps so no problems with doing them now.
This is an important technique you can use: paint black if its too cool and cover in aluminum foil if its too hot. I often cover my peaches in aluminum foil even if its not getting super hot since direct sun can heat things up quite a bit. On the other hand I will paint the graft union area black if I'm not getting enough heat but its sunny out. I always do this on spring grape grafts, grape grafts callous best in the 80-90F temperature range. I'm not sure how much parafilm heats things up but I bet it makes scions warmer compared to unwrapped ones.