testing and comparing on a Donic Defplay Clasic Senso (slow balsa blade, very soft feel)
RITC 755 0.5mm
Palio ck531a 0.5mm
doublefish 1615 0.5mm
TSP P1-R - 0.5mm
dont want to bore you with the details about how the testing was done....but it involved a robot and some crazy ideas to eliminate the bias of a custom swing.
Quality of topsheet/sponge (note all rubbers have stock sponge) IMO
1. TSP P1-R 0.5mm (chalky dull appearance)
2. Doublefish 1615 0.5mm (shiny plasticy appearance)
3. RITC 755 0.5mm (shiny plasticy appreance)
4. Palio ck531a 0.5mm (very shiny very plasticy appearance)
Softness of pips/sponge
1. TSP P1-R (assuming the soft version now)
2. 1615 tied with 755
3. Palio ck531a
Feel (dead to springy)
1. P1-R
2. ck531a
3. 755
4. 1615
Speed (stationary bat with fast semi low top spin ball driven into it approx 90 degrees rebound distance measured high to low)
1. 1615
2. 755
3. ck531a
4. P1-R
Insensitivity to spin (HIGH spin medium speed ball (enough to bend the pips) hit paddle at approx 90 degrees and rebound trajectory measured, this test also determines the ability to add spin of its own, or essentially grippyness. trajectory labeled low to high)
1. ck531a
2. 755
3. 1615
4. P1-R
Reversal (heavy headache ball shot straight at paddle and resulting reversal observed)
1. ck531a
2. 1615
3. 755
4. P1-R