I have to say sometimes you do get a prolem with the nail trainer and tips.
I think the ones from essential nails are made especially for them as seem to be a better fit, but this is good experience in trying to fit nail tips to awkward clients hands.
I always get a gap with my nail tips on my trainer although my smile line is blended perfectly. At the end of the day i am using this for practice and it i not a client but for blending, finishing, application of product and polishing it is excellent, just the daft tips dont fit properly, ive tried creative, Ezflow, NSI, star and othe lesser known companies,I think the problem is that the nail beds are very flat and most tips have a deep c curve, the best i found were eclipse tips by creative but they work out pricey when playing.
HTH
Best thing is look at essential nail site and get the proper tips or the lone airbrush nils theya e good for playign with so ive been told.