That's a pretty common problem with uncoordinated puppies trying to catch their bodies up to speed with their bodies. Patton was catching discs at 5 months or so, Pilot couldn't catch reliably until about 8 months.
Throw more rollers. Keep building the drive in hauling ass to get there, lots of tug on the return, every week throw one in the air and you will be able to tell when the dog has "gotten there" and is ready for more air throws. The rollers will also build confidence in the bite so that there is no hesitation snagging it out of the air when they do get there.
Also, have you taught an around, where the dog runs behind you (clockwise or counter, your preference) and then is "in flow" to drive forward and track? If not, I would start ASAP. Much safer take off, better chances of finding it to catch, and much better timing for you both on takeoff. I say "go" when I am going to throw the disc out so that the dog knows after they've gone around me, to take off! My dogs are 5-10 feet in front of me before the disc leaves my hand this way and they have a better chance of catching.
Also, long throws for puppies or green dogs can be demotivating. I would start short- no more than 10 yards, with lots of spin to get the disc floating, to give pup a fair chance at catching and so as not to wear pup out.
If you're getting lots of holes in those discs already, I'd upgrade to sonic xtras or super sonics in either plastic (taffy or candy) - taffy is my preference. They're a little heavier than what you have now though and will be more difficult to float for a pup, so I might go with the light sonic xtras and expect a few holes- it will happen eventually with almost any disc, unless you get a bite disc.
