Looks a good strong well-built hive. I would like a similar one in cedar, but have not got around to it yet. I also thought about trying my framed hives without foundation, but I think 14x12 may be too big - could collapse!
Not if you wire the frames first.
Simply drill 3 or 4 evenly spaced say 2mm holes equal distance down the length of the side bar's following the groove as a central line. Assemble the frame and nail it together, you will have to check for square at this point. Then thread the wire through the holes across down and back again. at each end half nail a frame nail wined the wire round a few times then drive the nail home. Before nailing the other end of the wire you will have to pull the wire tight in some way and be careful to keep the frame square I simply screw 4 screws into my bench to the inside corners if the frame and this works reasonable and after the frame can easily be checked and pushed back square if need be.
To be perfect we should fit eyelets in the holes but for an experiment the holes are just fine, I have started with the eyelets now as I know that I intend to continue this way.
I have found that if you give the bees a 1" starter strip they then build lovely straight comb, I started with smaller and I had to watch the bees closer as they could go out of shape at times but 1" seems to be a good size. I know one day a hive will go terribly wrong and I will have a bit of sorting out to do but for now when a comb is slightly out of shape I simply cut it a bit and push it back in shape.
If you are tempted then be aware that the bees are happy with up to 20-25% drone comb in the hive and you will have to get use to seeing drones so if you experiment with 3 frames this could all be drone. I experimented with a 14x12 last year with 5 frames wired and 6 frames foundation and the drone comb on the wired frames was quite something but I soon realized my mistake as my other hive although a standard national on 100% wired frames was fantastic and sold me on the concept.
I am yet to see evidence that my hives are a varroa factory that is often mentioned and one I expected, I have been monitoring throughout the season and not noticed high numbers, I did the other week spot an ant removing a varroa from one of my inspection tray's and this may be masking my level but recently I have done more drone cull and checked them but again not a great number. I have seen drones evicted from the hive with deformed wings so I know they are there and I expect a higher amount than normal and will start Thymol treatments early this year and will see what drop I get during that and I will be very surprised if it is not high or higher than I have had over previous years.
ps The TBH is Cedar by al means pm me if you need any help