Hi, sorry to hear about the bad news of your grandpa even if it was 2 years ago, he would be really proud of you for getting a tattoo in he's memory. You are actually best of going to the tattoo artist you are choosing to do your tattoo to also do the design for you. A lot of tattoo artists won't work of somebody elses work and will draw up there own version anyway, It's best to let your tattoo artist design it for you so it's personal between you and him and you can change anything that need's changing. Part of there job is to design the tattoo they are tattooing.
Good luck!
Are you going to bark all day little doggy or are you going to bite?