Well after my initial uncertainty I quickly became enamoured with the Thunderbird. So enamoured that I got a bit silly and ordered some more, realised I didn't need three and put one up for sale.
I can't stop playing them, such a thick growly tone. They aren't subtle or refined. And they really respond to pickstyle too, it really kicks up the aggro a few notches. With my current setup, I am very pleased indeed - I can easily achieve the Cheap Trick / Wishbone Ash tone.
I have ordered some replacement Gotoh tuners however - the current ones are fine but don't look quite right. The old-fashioned long stem tuners should finish it off nicely.