I can't understand why the manufacturers do this, but they only ever make one tip of French tip (or at least that's all I've ever found). With naturals they have ones for bitten nails, arched c-curves, flat nails, deep side walls etc, but with French they only have one type of curve in the well. Therefore your tips may be too curved for the clients' nails and so they are exerting pressure against the nail plate and hence why you get the pingers.
If this is the case then you will either have to tailor your tip by going anything up to 3 sizes bigger and filling down the sides to compensate, but by doing this you sacrifice some of the curve in your smile line. Or, you will have to advise your client that they aren't suited to white tips and would have better success with either sculpting or pink and whites.
Also the well of the white tip covers quite a lot of the natural nail, and the strength and adhesion is in the product and not the tip! Therefore you could cut out some of the well so that more of the natural nail is exposed so that more product can "bond" with the natural nail.
HTH