Thanks for your detailed answer. That is just the info I was looking for.
Am still thinking seriously about lots of zip for a front end cover.
But yes, if it is a good quality #3 zip, like the ones available from Warmlite, it will add close to an ounce, or almost 2 oz for the two I would like. There are lighter zippers from YKK, maybe they are #2.5, that weigh about 1/8 oz per foot, have lighter sliders, and are fine for an inner net door; but the slightly heavier YKK used by Warmlite is probably better for exterior use on an end cover that will be exposed to the wind.
"why does everyone pitch them so high off the ground, ventilation i guess but looks like a wind trap to me...
For a long time I used double wall tents with flies that did not come all the way to the ground. First thought about this when a friend purchased the SMD one person 'mid (Lunar Solo?) and told me she was very uncomfortable in the heavy condensation during an all night rainstorm. Her trekking pole was short, so the sides came right to the ground. Then noticed that the GG One's ends extend well beyond the floor sidewalls, but in most pitches I've seen do not come to the ground - that tent has been well reviewed for control of condensation. Both are single walls. In a double wall with good venting, it may be a different story with a beathable DWR or net inner to shield one from the condensation.
But if using a single wall to save weight, IMO more ventilation is required to keep condensation to an acceptable level, acceptable to me, anyway. You point out that when walls or end covers do not come all the way to the ground, the tent will be more vulnerable to the wind. Can't argue with that, but there continue to be good reports of the GG One's performance in the wind.
I suppose it is a trade off. I would rather have the ventilation with some balooning in heavy wind, than a steambath with coverage to the ground all around.
It probably depends on where one will be using the tent, such as the wide open exposed terrain of Iceland or Scotland, as opposed to below timber or tree line in the Rockies or on the AT. My choice is probably also based on good experiences with tents with good ventilation all around, not to mention the reports of many shaped tarp users who are not having their tarps blown away when pitched raised above the ground. To each their own, I guess. All of these designs can be done with the canopy walls and endcovers coming all the way to the ground if that is what one wants. They do tend to weigh more that way.
Also, there is a big difference between sleeping under a tarp pitched several inches off the ground, and sleeping under a tent canopy also raised several inches, but with a bathtub floor that is recessed inside and attached to the canopy with some arrangemet for perimeter ventilation. That difference may be one of the best reasons for carrying the extra weight of a single wall tent.
The tent you want may be one that can be pitched high or low, depending on the setting of the trekking or tent pole length, and how the tent is staked. So you might want to look for that feature in designing or purchasing a tent.