If your worried about a high dextrins/body, water the beer down a bit and make a low gravity session beer. They are best made with a high mash temp.
Im curious about this. I make mostly low gravity bitters and milds, and always mash around 66. The body is not too light, and they are highly drinkable. FG is usually 1.010 - 1.008, and i use less than 10% crystal for most. I really like the way they come out. Why do you say they are best made with a high mash temp? Dont they end up cloying and sticky?
To relate it to this post, i just did a double batch of mild. Its more on the dry/light bodied style ( for more malty i use lots of biscuit and crystal ), and i accidentally mashed at 70 also. I just left it ( never mashed that high before ). The last batch was around 66c, exact same recipe etc. Will update when im drinking it.
Let us know how it turns out.