The builder, Fred Rodger in the US, says it fulfils all his expectations but needs a skeg to stop it turning too fast. A skeg is under construction. He is also rethinking the outrigger and thole pin arrangement.
Thole pins are very ancient and still used in many parts of the world, mainly in traditional fishing communities. The rope holding the loom of the oar against the thole is called a humlibaund in Scotland and an estrop in Catalonia.
Fred doesn't say how long his oars are but Gavin thinks they may be too short.
There are lots of formulae for calculating the 'correct' length of oars of varying complexity ranging from a simple 'half the span, times three, plus six inches' (span is the distance between the thole pins) to the widely-quoted Shaw and Tenney equation that you need a computer to calculate.
I personally use trial and error. Start with oars that are too long and take them out for a thrash. Then cut them down by half an inch. Repeat the process until you feel really comfortable. Then go rowing.
With modern oars, you will need to adjust the button that holds the oar in place against the rowlock to maintain balance, but with Fred Rodger's thole pins it will mean simply repositioning the strop.
It is also worth looking at the height of the rowlock. Even a small change in the height will make a big difference to the height of the handles above your knees - raising the rowlocks just a little can transform an uncomfortable and cramped stroke into a lovely casual swing.