Looking for thoughts, pros, cons or advise

So I'm going to purchase 2 Ball Pythons at a reptile expo on March 31 and I would like to have my enclosure complete, setup, tested and proven good by then. I have come down to 2 ideas. First off I enjoy building things so I will be making my own. I am happy to look at commercial stuff for ideas but I will be building it even if it cost more. Both ideas are to be made from waterproofed sanded 3/4" plywood or 1x? lumber. I'm not a fan of Melamine. thermostats will be used to control all heating devices.

Idea #1 is a rack with interior dimensions of 36 wide X 24 deep by 6.8 tall per shelf to fit the Hefty storage totes which come in a fairly good size range. My thoughts are to close all sides, top, back and have a front Plexiglas door. My home can get down to 65F during the winter so I need to retain heat as much as possible. I know some ventilation holes will have to be made in the tubs and the outside of the rack to allow air flow. I plan on using larger sized heat tape like 12" on the shelves but as it won't help much with ambient temps I don't know how feasible this approach is (though i figure any source of heat should help some in an enclosed area).

Idea #2 is to do 2 separate single snake enclosures that can stack on top of each other. Interior dimensions of 36 wide x 20 deep x 16 tall. Inside each I would place an 80 watt RHP on the ceiling off to one side. The front would hinge down with a Plexiglas window in it. I was thinking to still use tubs with lids inside of these enclosures till the snakes were large enough to be in enclosure itself. The tubs inside the enclosure should help with the temp regulation since its a concern for me. I can still use heat tape if needed to add a temp gradient for the tubs but this will allow a controllable ambient temp.

I am leaning more towards Idea #2 but not sure about the tubs inside it. Also not sure what size snakes I will be getting. Most likely juvenile or hatchling so it seems common theory is that the enclosure would be too big to start with. I can't come up with a negative so was hoping someone could chime in and catch something I'm missing. Also I have an enclosure I built a few years back for our bearded dragon that measures 4'X2'X2' and uses a combination of CHE, UVB basking light and spot light (all thermostat and timer controlled) with Plexiglas doors that I need to do very little to and it maintains temps great for our Beardy. I know BP's are a bit more picky about husbandry.

Thanks for your time and advice. I will be adding pictures and 3D cad drawings once I've actually started to build.

Gunkle