Been a long time since I experimented with duds. Supposedly it is the binder in milk or cream that makes leather more consistent. It isn't the milk fat so going from low fat to high fat products doesn't have much effect on how well the milk product binds with leather. I have tried from two percent to cream without much different result except it being harder to soak tips in thicker liquids.
Others have used oils or solvents on tips, or so they claimed. No idea if there is truth to these claims.
My tips seemed to work best when I soaked them in whole milk for three to five days in the refrigerator. I tried really crushing down on the tips and didn't like them. I wasn't really looking for a harder tip, just more durable. so I flattened down to about stock height.
I started sorting my Elkmaster's by size and weight before soaking. The ones that were extremely light hit the trash can. I needed a tip a time or two when I didn't have a dudded tip handy and found that the tips sorted by size and weight played just fine for me without dudding.
In my sampling I didn't like Le Pro. Quite obviously others had different experiences. Hides being natural products the leather can vary a lot from hide to hide and place on the hide too. Then there seems to be dozens of tanning processes. The leather is often in different stages of decomposition before tanning too.
I would have thought that a synthetic would have taken over from leather long ago. The new super pricey layered tips may bring in some things that weren't possible to price competitively with fifty cent leather tips. Of course some rules ban nonleather tips.
Dudding seems to make some marginal tips playable. If I sort and start with good tips the milk or whatever seems to have little room to be absorbed. Some tips swell to maybe three times their original height but I question what all they have absorbed to do that, and does it remain in the tip after squeezed?
Hu
