Well the first ones you have there are the ones I used forever with my older ski, they did ok, but I replaced the suction cups with cords that I made the right lengh to hook on to certain places on my ski, on the front I hooked aroudn the mirror, which works but always wished there was a better place on the front of my Yamaha ski to hook too. These are well made, but are inflated with air with a air pump and I have had them crack and let the air out.
The newer black one you have there are what I use on my new ski, I got rid of the strapes that came with mine and bought 2 short bungie cords that work better I think, definitly faster to hook up, cause you just streach to the back hook just like you have yours hooked up on the back. But on the front I tried it like you have it pictured there and if I pushed the bumper towards teh front at all it would just move very easily, so I do not see how putting that rubber thing inside the front compartment will really hold the bumper in place, it did not on mine very well. I now hook the bungie in the front to where my front compartment lid attaches, it is very sturdy there but I can not shut my front compartment when its hooked up.