Nouvatan is great however it is a golden tan so completely different colour to LA. I stock both Nouvatan and LA Tan so I can offer a golden based and brown based tan. If you are looking for a similar colour to LA then you are best to try some samples from other companies that stock brown based solutions. Some companies you may want to contact are (sorry for any repeats): Suntana, White to brown, Xen Tan, Laurens Way, OMG!, Fresh Indulgence, Trinitia.
Everyone seems to have there own preferences, likes and dislikes when it comes to tan solutions. Best to just give them a try and judge for yourself. If you have a search through threads you will come across a wealth of opinions for and against various brands.
If you are still having problems with wear off then it may be worth while double checking your gun settings and spraying technique. I would also review the solution % you are using on your clients, generally stronger %= poorer wear off. HTH x