Hello, I have an orange one of these. The tubing is Reynolds 725 and it is great.
I have just overcome the lack of disc brake mounts (see my recent thread on the subject!) but using a slighly modified Quad disc brake adapter that I found new on ebay (the seller has lots for approx £15 if you are interested).
It is ideal for the Singlespeed frame as it sits on the inside of the dropout. I gave it a reasonable test run today and it is solid - I am v happy so far.
Also, fitted my PCC 27.2mm dropper seatpost with remote; have had this 'in stock' for ages but the ability to switch between a full height for most efficient pedalling and a 4 inch drop is just great.
I have two other Dekerfs which I also love but the singlespeed is the one for life!
I am running mine with 80mm Fox RLTs which are enough for most circumstances.
Enjoy your build. Also, I have a couple of white and green Dekerf team tops and some bibs which are about to be put up for sale - if you are a 40-42ish chest then let me know.
Dekerf Singlespeed, Dekerf Phenomenon (both for sale)
Bioracer Columbus Nemo roadbike, 10 speed Campagnolo
Merlin Magia roadbike, 11 speed Campagnolo
Venom Columbus Max roadbike, 10 speed Campagnolo