Dunc;
Firstly, I love the Tich design, although others will disparage it – too small, too complex, too large (that's the gauge 1 crowd).
I'd think that if you have made a couple of stuart kits, a Tich would be fairly easy for you. Remember that there are quite a few variations of Tich; 3 boilers, at least 3 valve gears. My first locomotive was a "large boilered, slip eccentric geared" Tich, and she's still going strong, although the paint isn't!
I built 2 Tich boilers; the first almost in line with LBSC's writings; nutted firebox stays, etc, and I did not even know how to anneal copper at the time. It was a failure, but I learnt a LOT about it, so Tich boiler #2 (from a "Reeves" kit) took 11 hours to complete, and its still going strong.
Books? Do you have Model Engineer? Lots of info in there, but you may have to read between the lines. I don't know if I'd worry about the Tich book – it is entertaining, but you probably know enough already.
Another JohnS.