If your fence is 6' or higher, the pole beans will work well. They will spread sideways at the top of the fence. Just plant them anywhere from 6" to 18" from the fence and they'll find it. I have no experience transplanting beans, so I don't know how well that works. Being that you are in zone 6, the length of your growing season shouldn't require you to worry much about head-starting limas. I might suggest instead just soaking the seeds 2 to 4 days ahead of time. Here in zone 5 I sow them around the 1st week of June, though I'll delay a few days sometimes if we have a cool streak.