One rule for zoom lenses they must always be thought of as being their longest focal length. E.g. 25 to 50 handles like a 50 50mm. 100 to 400 treat it as a 400 50mm lens. Use the zoom lens which will just do it all with the one lens if you can.
Stupid thing i didnt type it as written. I think you get what I am saying. Heaven help us if they make a 50 to 500 lens. It will need and handle as would a 500 fixed lens. While talking about long lenses they usually have tripod mounts. Make up an adjustable cord with a loop in one end and a screw bolt other end. Screw bolt into lens put your foot in loop. The cord make it fit so when lifting camera upwards you will find it acts just like a monopod. Nice and steady quick handling.