The build
I built the in a two piece configuration and I am very glad I did. This is a significantly heavy speaker. The only modification I made was to make the total speaker width 43cm. This was done to maintain specified volumes.
Material was was 24 mm Baltic Birch for all sides, backs, and fronts. The only exception was the sides of the top box, which utilized leopard wood finished to 24 mm. All bracing was 18 Birch plywood.
Finish was lacquer coloured with alcohol based ink. It was my first time using lacquer and as a result purposely sprayed the panels prior to assembly, as a result, it made for some very careful clamping processes. Most pieces had about 7-8 thin coats.I haven't decided on the feet design yet and for now the speakers are sitting on cut to size gym mats. The build took me about 8 week with days between 4-8 hours, the painting added to the time significantly.
 
The Sound
For a wide baffle these speakers image very well and present a wide and tall sound stage with great instrument and vocal separation. It's a dynamic speaker and has great PRAT. They present piano notes better than anything I have had before, great tonality on instruments, the clarity of presentation   Nylon strings on a classical guitar made me smile as did many other sounds. I built the level one version which is very smooth on the top end with lots of detail like voice inflections, I suspect it's due to the copper caps. In the end the ultimate test of any speaker for me is how well it engages me and holds my attention. With the TL3 I found myself listening through full tracks on a regular basis. The speaker has a magical quality of seeming to present each note in a way that I found myself thinking that I understood much better what it was the the musician was trying to do.
Songs that I once thought were drab little pieces suddenly hold my attention. I suspect I am going to be content for sometime. I am using two different integrated tube amps, a Line Magnetic 805ia (45 watts) SET, and a VAC 160 sigma SE (85 watts) pp.
 
Many thanks to Troels for quick responses to a few very amateur questions...it was my first build and getting quick answers certainly helped move things along.