Runner Beans from Seeds

Question regarding growing runner beans from seeds. I recently planted a dozen runner bean seeds and there was a significant difference in the height of the plants, three of the plants were about four times in height of the smaller ones.
Would it be beneficial to grow more seeds and just pick the stronger plants in height? or perhaps the other plants will catch up in height?

 

I sow my Runner and French beans individually in Root Trainer cells at the end of April, weather dependent, then keep in the greenhouse. They germinate over a week or so; about mid to end of May I harden them off and plant them out by which time they are all about the same size.
The Root Trainer cells make handling the individual plants easier and there is less root disturbance.