i have only been training for about a week but i am having extreme difficulty in applying the tips.it seems that if i pick one that seems to 'fit' t doesnt stick, if i pick one that is way too big then it does fit !!! is this right?? also it says in the book that the tip shud only cover 30% of the nail, but all the tips to go with the nail trainer cover about 60%,!!!! plz help i really want to be successful at this.x.