Welcome to the forums, Joe. I still have the document that tells how to adjust the timing on the three cylinder A4s. I can send you a copy if you give me your email. Click on my Tardis photo, select start a conversation, and give me your email address. I'll send the document along to you.
BTW, setting the timing will take a while as it is somewhat involved in getting access to everything. I was going to try it on my Mallard while I was at the US National Summer Steamup in Sacramento, California since there were a lot of experienced RR folks there to help, but I got lucky. Wuhu was an exhibitor at the steamup and they had brought along their factor prototype engineer. He did all the work for me when he saw me running the Mallard and noticed the timing off. He did a big tear-down, set the timing, put it back together, and had me run it. He wasn't happy, so he did it all over again, and then was happy with the results as was I. It took him about 1 1/2 hours and he worked very fast.
I had posted a number of pictures with some of the disassembly in the thread mentioned in message 7 above, but it seems to no longer be available.
If you are getting water/steam leaks from fittings, you will need Regner copper crush washers (see message #10) above. The fiber ones originally used will fail and were a bad choice. I discussed this with the Wuhu factory engineer and the Wuhu General Manager at the steam up. I gave them some samples and they were going to make the change for future designs and builds. I don't know if this happened, but they were very interested and saw how they worked on my engine.
George