preferred method for connecting false bottoms?

I use both...15 gal keggle (for 10 gal batches) and 10 gal cooler (for 5 gal batches). I rarely use the direct fire feature of the keggle, usually I just add hot liquor if needed (Winter)

 

I use about 5-inches of 3/8 inch (I.D.) copper tubing with compression fittings between the false bottom and the ball valve in a 10 gallon Igloo cooler. Most hardware stores only sell rolls of tubing, however a local refrigeration repair company in my area was happy to sell me short lengths for cheap.