Thanks for the explanations Kevin, it's all good. I guess I can a be a little too stubborn at times , so I take my share of the blame...

One of the reasons why I never took up the ...Nc6 line is that after 6.Nf3, (6.Bg5 being considered as "risky" for both sides, but probably more so for White), black's best move is 6...Bg4, which leads to an endgame where neither side has much, and it's practically impossible to play for a win for Black... or White!.
There's been a recent try to improve the variation for white with an in between check on c5:



[Event "Analysis"]
[Site "Canadian forum"]
[Date "2018.12.12"]
[Round "0"]
[White "Not important"]
[Black "Not importan"]
[Result "?"]
[PlyCount "30"]

1. e4 c6 2. d4 d5 3. exd5 cxd5 4. c4 Nf6 5. Nc3 Nc6 6. Nf3 {This is the most
solid line here, after which ...Bg4 is thought to be best. The main line now
leads to a completely equal position, but there's a recent new idea which is
causing black some problems.} Bg4 7. cxd5 Nxd5 8. Qb3 Bxf3 9. gxf3 e6 (9...
Nxd4 $4 10. Bb5+ {And White wins.}) 10. Qxb7 Nxd4 11. Bb5+ Nxb5 12. Qc6+ (12.
Qxb5+ Qd7 13. Qxd7+ (13. Nxd5 exd5 {Unlike the line with 12...Qc6+, here
Black's King hasn't moved and can therefore still castle, so any move other
than Qxd7, which tranposes into the endgame, is just bad.}) 13... Kxd7 14. Nxd5
exd5) 12... Ke7 13. Qc5+ $5 {This was first tried by GM Grischuk in a rapid
game. The move looks absurd because Black can retreat his Knight to d6.} (13.
Qxb5 Qd7 14. Nxd5+ Qxd5 15. Qxd5 exd5 {This has been played hundreds of times.
Unlike the other line, Black's King is here on e7 rather than d7, but the
position is so equal that it doesn't really make much of a difference.}) 13...
Ke8 (13... Qd6 14. Nxd5+ (14. Qxb5 {This has been tried also.}) 14... exd5 15.
Qxb5 Rb8 16. Qd3 $5 {With an unbalanced position.}) (13... Nd6 14. Nxd5+ exd5 {
And here both 15.Qxd5 or, better, 15.0-0 give White good compensation for the
piece, with Black's King being stuck in the center for a while.}) 14. Qxb5+ Qd7
15. Nxd5 exd5 {And here White can retreat his Queen to b3 or d3. Since Black's
already moved his King, he can no longer castle, which could cause him some
headaches in the long run.} *