None of those people were going fast enough, that is the problem! But seriously, I would not ever recommend riding the bike up the ramp.
It looks like you picked a nice looking ramp, particularly because of the extra width. I like to power the bike up the ramp very slowly while I am walking beside it. Do the reverse on the way down, with your hand on the brake.
Heavy bikes can be a little tricky coming down because you can only cover the front brake, and most of the weight is on the back wheel. The front tire will slide a little bit if you get going too fast and then jab the brake. I suspect you will not have this problem with the PX150's because they are not very heavy.
Take it slow and easy, and you will be fine.