Could you not have beds on both sides so you can rotate and see what works best where? If not I think left makes more sense. Plants need more sun when they are young and the weather is cold is my best rationale. I grow in a north facing balcony. It gets sun mostly from the west, some from east when the days are longest. The westerly sun exposure also creeps up and fades off with the growing season and only 1/2 to 1/3 area gets any sun throughout. I have devised ways to maximize the sun exposure as best as I can but I have the flexibility of moving the containers. My peppers are now growing in bright light with maybe an hour of sun but doing ok all things considered.

Are you in a moist cloudy coastal area, or a dry sunny one? I live in Colorado and I’d definitely choose the early season sun since plants get burned in August. But in Oregon...if it’s wet and cloudy, I’d choose late season sun. Tomatoes, peppers, and cucumbers are all warm weather plants and will want the season to last as long as possible. But I also like PP’s idea of doing one on each side!

Since most vegetables will take as much sun as possible.....one seldom sees farms in the woods :-)........I wouldn't use beds along the fenceline for this purpose but rather site the beds in the center portion of the garden where they will receive full sun all day long as much as it is available.