Nexgen top gel help please!

[Libra3]

Hi all! Latley I've had quite a few clients requesting Nexgen nails. I've always used traditional acrylic and gel systems and have always viewed the dip systems as temporary nails and have stayed away from them...but of course I like to give my clients what they want so I invested in the Nexgen system. I've been doing nails for 15 years and figured this would be simple to do...however I seem to be having a hard time with the final step of the system. They refer to it as "top gel". I followed the tutorial exactly..after buffing I remove residue,then applied activator, let it dry and then applied the top coat. it looks good going on, but then it seems to seperate and or crinkle resukting in a nail that diesnt look ir feel smooth in the surface. The top coat is streaky and rough when it dries. Also, my brush hardened up after doing the first nail. I had to clean it with Acetone to even make it usable again. If anyone knows what I may be doing wrong,please let me know...I cat send clients out of the salon like that.