I agree, with one small exception. The riffle shuffle for the Savant deck needs to be done 'properly' for this to work, so I do a couple of riffle shuffles myself and then ask the spectator if they would like me to shuffle again. Once done, I say 'any more' until they are totally convinced it is well mixed.

Now for the exception ... when I want to involve the spectator in the physical mixing process, I get them to cut the deck into multiple piles (5-7) and then ask them to pick the piles up in any order. Once done, I ask if they would like to do a final cut and this has all proven to be sufficient to convince them that they have mixed the cards well. All just my method, I am sure there are many more.

Either way, my Savant deck rule is: riffle shuffles = me, cuts = spectator. The coloured-in red dot in the centre of the card backs helps me keep track of everything during the cutting process. As long as I am seeing red dots on every cut, I am happy.

But do your savant decks cut cleanly? I often have a card sticking to the bottom which falls off from the top packet.

I have made up a couple of Savant Decks, along with the supplied one, and they all operate fine. As mentioned above, I use a red dot in the small centre circle, on the back of the all of the short cards. This gives me visual feedback to ensure that the 'right' cards are on top after cuts.

Not sure what you have tried to remove this issue, but it might worth trying a couple of things such as: cleaning the cards, very lightly powdering the cards, breaking them in thoroughly to the point that they form a slight bend in the deck, making up other decks to see if the issue persists, etc.

I am sure others could suggest other/better ways to remove the issue.