Earnings are shown on the bottom of the page in the Summary section after you've selected the flights. They show M+M award and status miles and Germanwings Boomerang miles. IIRC, booking classes appear only in the booking confirmation.
Since the website only shows the cheapest fares available within the 3 fares, there is no way to select a higher booking class in order to earn more miles. The only way is probably to wait until the lowest fares are sold and the price went up to the next level.