You've probably long since reached a decision about your tunnel layout, but I'm new here so thought I would tell you what we do. We don't use beds, except one long one along the south side for salad and carrot crops. Our tunnel is about the same size as yours, just a bit wider. By not using beds I can move my crops around in some sort of rotation but quite flexibly. Also there is no part of the soil which is never cultivated. I use walk boards so the soil is not compacted. We are very cold here so have to grow runners and climbing french beans inside, also sweetcorn and squashes, as well as tomatoes and cucumbers. I have tried growing all of those outdoors with no success ! Some years I grow the climbing beans under the crop bars on the north half of the tunnel, so they make short rows north to south. Other years I grow them in wigwams between the crop bars with squashes climbing along the bars. This year I have done it differently and the beans are in a long east-west line about 2' in from the north side.
I always put the tomatoes near the south side, under the crop bars one year and between them the next, also rotating which end of the tunnel they go. Cucumbers go somewhere near the middle to be away from draughts, with fleece around them for the whole year. Sweetcorn goes in a block near the louvres at one end or the other for good pollination. Courgettes fit in wherever they can, as do early lettuce. Finally the things you would normally grow in the tunnel are in my greenhouse, which is itself inside the tunnel !! So chillies, peppers, aubergines, some tomatoes and so on. If the greenhouse was outside it would have blown away years ago !
We are lucky in that we have deep soil so beds are not essential.