Simple answer is, yes. Practice makes it easier.
However, I also find it somewhat easier for me to grip smooth (no mill on the edge) coins if I place them deeper into the palm. I achieve that by pressing a little harder with my fingers.
Also do note, two weeks are not too that long of a time for classic palm. I would suggest these exercises as well since you are getting more comfortable with the classic palm.
1. be able to write with coin palmed in your hand or other daily activities. This achieves two things. When classic palm is first learned it has very awkward look (David Williamson refers to as bird cage look). So first, it dulls the awkward look and allow you to have more natural look on your hand. Second, as the Professor said "If you can't practice being natural, be natural at being unnatural" or something along that line. If you are doing normal things with coin in your hand, though however odd your hand position may seem, it will be natural to you, hence appear natural regardless of the how awkward your hand appears.
2. Start palming more than 1 coins. Once I was comfortable, I moved up to 2, 3, and now I can hold up to 6. I'm not saying that to brag, considering that palming 6 coins don't mean a whole lot seeing that usually the most you need to palm is 4 in one hand, but it allows you to hold on to coin better, and it will help you with the problem you currently have, palming coins that are smooth.
3. If you have interest, I would say start learning the muscle pass. It is such a great utility move/sleight. So many applications that are being discovered. I learned that because of the nature of the sleight, it will strengthen your classic palm when you are learning muscle pass. I won't go into details, but you should check out "The complete muscle pass" by David Kong or "Muscle pass" by Jay Noblezada. Though I think David Kong has more applications, they are both fairly good place to get started on the muscle pass.
I know I said a lot of stuff, but these are what made differences on my classic palm. Hope these helps.
p.s. I heard about practicing with wet hand, and I'm sure that helps with a lot of sleight and etc, but I say unless you have constantly sweating hand, I'd say it's not as vital... Though I do admit that it can only help.
sad times.
