[Bill]

That's a very good instructor that you have. Martin helped me over a few hurdles in diving. I don't think any one has the best answer yet. Try to set up a training program that you can stick with and the times will keep improving.
No goggles was an experiment and didn't make much difference in time but prevents making some mistakes (surface prodcedure or checking the watch) so I stayed with it. I can relax more with my eyes closed but opening them helps prevent vertigo when the safety diver seems to move me in the wrong direction and concentrating on a blurry point helps near the end.
Contractions are different for each diver. As my times improved, they started coming earlier. Now the first are mild at about 3 minutes and about 5 minutes is the worst.