Yes, I have the full version, so I can render bigger. I shouldn't take much credit for the clouds, as they are a tweaked version of the Cumulus Humilis made available by NWDA (only cost a few euros, and can be used with the free version). These clouds have a more complex node network than the standard ones available with the program. Since the node network is copyrighted, I can't share a clip file (but if you did buy a copy, I could share settings).
Another thing you could try is re-seeding your clouds - go into the Density Fractal and either hit Random Seed, or simply change the number manually. I had to do that a few times before I got these ones.