I made my own also. Still using it.
With a 16 X 20 furnace filter, I don't have much air restriction, if any. I vacuum the filter weekly and replace it when lint impregnation begins (~monthly). I've never had wetness on floor or condensating anywhere.
My main forced air return duct is in the utility room (basement) with the dryer. I added a closable vent to the duct to draw the heated/humidified air into the forced air system during the winter months when the furnace runs and the dryer is vented to the filter box. I check the furnace filter often and have found no extra lint build up due to the dryer.
Steve
41N