Glad to know you don't seem to be taking my comments and suggestions personally.

I do think that you guys are doing a pretty good job but it's still really easy to get itchy when so many things are still a mess. And, of course, progress always seems a lot slower than would be preferable. (The sad story of most all programs.)
It tends to happen that people get either promoted to management or elect themselves to management without any idea as to how to actually do their employee's job. This is a big mistake as it puts managers into a position to make decisions which they are way too inept (in that field of knowledge) to make. A good manager would attempt to get input from people who actually have an idea about what they are talking about but well... Dilbert comics wouldn't exist if good managers grew on trees.
As for porting to C#, that would of course need to be done the same way the TAS7 versions are done: one module at a time. It wouldn't be that much different than the switch from TAS5 to TAS7. From what investigation I've done it seems like TAS5 and TAS7 do not bear a huge resemblance... It seems that there is a very knowledgeable core group of people who know TAS in and out but they are very, VERY few compared to the people who can help and/or answer questions about something more mainstream like VB, JAVA, C#, etc. Still, I suppose TAS7 isn't so terrible even if it is only used by about 10-20 people.
If you are indeed going to use SQL (which you definitely should do) then the opportune time, in my opinion, is when you are porting the app out of Tas5 anyway. Btrieve is a dead horse that has been kept on life support for many years too long. Both Addsum and CAS advertise support for SQL and ODBC natively don't they?