You should gain an advantage by your plan but I cannot predict how much of one. I've heard the comment that each greenhouse film setup within the original structure is expected to have a net gain of one full climate zone. However that is a simplistic statement.

In years past I've set up a structure within a greenhouse using a canopy frame with shorter legs. Then I also covered plants under that with floating row cover. I did suspend fans at both ends within the canopy framework to help move air around. I monitored temperatures at three levels with thermometers that would save the high and low temperature readings. The main problem I encountered was that there were "cold spots" where temperatures dropped below freezing and I lost 10% of my plants (tomato). To me that was unacceptable for that crop and I've been heating all my structures with wood stoves for the last 5 years- a much simpler and more reliable approach. I still run circulation fans; I close cracks as much as possible ( a can of "Great Stuff" goes a long way but it looks like crap); I use at least 2 inflated film layers over all my structures, one benchtop even has bubblewrap sandwiched between 2 plastic layers. Yet there is always a point where I wish I could gain a few more degrees inside these structures.

The expert on this subject IMO is Dr. Adam Montri, Michigan State University. He has done more research on this concept than anyone I know. His setups may not fit your system but the ideas are somewhat the same.

I just completed a home made greenhouse 10' x 20' the frame is wood I constructed myself the sides are a material called sun selecter greenhouse plastic I wanted to make the side two lawyers with air bubbles between them for insulation but my neighbor is telling me this will block the sun. So really I don't know what to do. I have a ceramic heater inside and a fan turned on 3 hours a day for air circulation. During the day if it is sunny the temp can reach 55 but during the night with the heater all I can get is 40 I am new to this and I don;t know what I am doing,

The daytime high is puzzling since in most greenhouses you will need to take measures to drop daytime temps once the sun comes up. I've seen a few pictures of wood frame greenhouses that cast considerable shade but even so your daytime temps should soar once the sun shines.

At night everybody who owns a greenhouse would like a few degrees of warmth. With my 30x96 greenhouse I need to fire my woodstove as hot as I can to get a 20F change (from outside temp) most nights. That's a main reason that I won't be moving plants into it for another few weeks.

The low r-value makes it very frustrating to try to heat a greenhouse. I like that I have wood heat, but I am starting to think of it as something to use in case of unseasonably cold weather, rather than for use every night of the spring season. At this point in the year, it's easier to just pick up my trays of plants and carry them inside for the night than it is to worry about the greenhouse heat.

I just constructed a benchtop hoophouse within my large greenhouse. Just has a layer of 3 mil plastic over it and an old comforter tossed over that at night with one heat lamp bulb inside with all the plants. Bench top is 6' X 8' so it can hold alot of flats. Works fine for me keeping my seedlings and trops from freezing rather than heating the entire greenhouse. I still fire up the wood stove if outside temps will drop down past 25 degrees for the larger, yet hardier stuff I don't have under the hoophouse. Also, my father-in-law/neighbor's dog comes over at night to sleep in there and always expects me to build him a fire so he can curl up on a blanket near the stove lol. If it's cold enough I oblige him =)