[Antennas] 160 meters with short dipole

[Steve]

I've got 80 and 40 meter dipoles on a common center insulator, about 35 
feet off the ground and fed with 450 ohm open wire transmission line. I 
don't have room for a 160 meter dipole, so I'm wondering if I can use 
this dipole combination on that band.

Any thoughts or recommendations about how to feed the dipoles and the 
most appropriate type of tuner to use? Of if it's even worth trying?

Thanks.

Steve