I will be getting some modifications done to a shower for my mother, who is elderly and disabled. I'll be getting someone to remove the shower screen and raise the shower floor level to be flush with outside. The primary focus is having a non slip surface in the shower. I've been recommended R10 and am looking at smaller tiles, such as 100mm, or up to 200mm. I've been told that the smaller tiles will offer more grout in between which can improve non slip. My main query is do you find this to be the case, that smaller tiles with grout will ofer additional non slip protection? And am I on the right track with getting R10 tiles? Thanks