This might make sense time-wise, but it's huge step in the wrong direction in terms of customer experience.
Yes and no. Yes, in that an indecisive customer might just opt not to buy one. No in that if I'm in line I don't want to be held up by that indecisive customer. It sounds like they'll push you toward one of the pre-existing combinations. In 5-15 minutes, that seems reasonable.
Also remember that this is likely only for the initial rush. Once demand is more normal and supply has caught up to whatever that demand winds up being, I'm sure it will be more like buying a watch at a jeweler or department store. Macy's or Rogers and Hollands don't need to deal with potentially large crowds or spiked demand for a single product.