Maybe Yak, but then this OP wants to fly indoors in a hall, and knowing the stall speed ain't gunna be any help at all, for one, as stated, without really accurate telemetry from model to pilot, he isn't gunna know what speed it's flying, and two, if he wants to turn around at the end of the hall he will have to be travelling somewhat is excess of minimum, otherwise the thing will just flop on the floor. Your Reynolds might be good at 5 m/s, but I bet he wants to go a bit slower than that...If the object is to fly this thing indoors, then perhaps the questions he needs to be asking is how to build the thing really light, with adequate strength.
Evan, WB #12.