Well, IMO, and as many knows I might be different than many, it plays a huge role, size and thickness in low winds.
Meaning when below 10 knots, you (I) are much better off with a bigger and thicker board, the lower the wind.
I got 4-5 boards different sizes and thickness, and use them all depending on wind, when below 12 knots, otherwise the smallest ones can work just fine.
Even with really big wings, there is no substitution for size and volume, in terms of being able to go really low in marginal winds, and the bigger ones are a lot safer and easier to ride in extreme lulls too.
Most others will probably say it does not matter, if you use a big wing, but trust me, it does
So if your goal is primarily low wind, dont go with the smallest board.
If a wide windrange and limited budget, you can go for a small board and simply dont foil in really light winds.
And if a wide windrange and possible, get two boards.