Since your playing mobile, I assume your having most problems in the coin rooms? That being the case, you can only guess as to the speed based on your opponent tier, and level. The rooms play a big factor to your speeds also.
When I play coin rooms, best rules of thumb is this:
Longer irons, full back spin, pin in back of green, or added tail winds, I aim for middle of green.
Middle of green, pin placement, aim for front of green, again full b/s. You're going to get roll out no matter what.
Shorter irons, no spin, let irons do the work for you. Wedges of course, fire at pin., no b/s.
With head winds I aim 4 to 5 yards short of the pin.
Tweak for your ball and iron combo, it should get you closer.
This has worked for me, hopefully others will give you advice also, and maybe you can refine all ideas to fit your game style. Good luck.