I am always confused on deciding the proper size of my racket's grip. I have one Yonex Arc10 (G5) and I wrapped the original grip using a Toalson Asterisk (0.7mm) overgrip with 50% overlapping. The other racket is Victor LYD (G2), I removed the original grip and wrapped it up with two layers of Toalson Power Grip (0.7mm) with 50% overlapping each. In the end, I got my Arc10 has a slightly bigger grip compared to my LYD. I tested both rackets last night to try out various shots during some warm ups and exercises. I found that the LYD with a smaller grip was easier to handle and I can easily change my grip from the basic to bevel to thumb to pan-handle variously but it felt a bit unstable as it can be easily rotated by a simple movement and I had more error shots compared to the Arc10 with bigger grip. OTOH, I found that the bigger grip is more stable to execute power shots like smashes and clears. However, it didn't do as good on more delicate strokes like net or drop shots. My palm length is ±19.5cm from the base of the hand at the wrist crease to the tip of my middle finger. My friend told me to get used to the smaller grip as it can provide more shot variations, and as long as I can hold the racket with the basic grip without having my little finger touching the fleshly part on the palm under the base of the little finger, it shouldn't be too small for me. Is this a correct idea ? I know this issue is very subjective and each preference may vary among players, but is there any general formula or the "rule of thumb" on measuring the proper grip size as a basic guidance ?