Silicone feel
Specify the squeeze, rebound and touch you want; final feel needs a physical sample
Silicone squishy material, color and finish
Specify soft silicone for your custom squishy brief, then review squeeze feel, rebound, surface finish and color on a physical sample; screen colors are only a visual reference
Color approval
Use an agreed color reference and compare it with the physical sample under suitable light
Material test reports
Discuss which test documents apply to your intended product and market