Implant size adequate?

Hi, I have a patient who wants to have implant(s) to replace missing teeth #12 and 13. Mesial Distal distance is about 11 mm. I don't have enough room for two 3m implants. I plan to use a 4.3x13 mm implant for a single crown as shown on the attached pictures. Would it be acceptable? Patient don't want bone graft for a bigger implant. What other options do I have. Thanks!