Topband: Improving Inverted "L"?

[Mike Kroh]

I recently put up an Inverted "L" for 160 which I'm not completely happy about and would appreciate any helpful suggestions.  The vertical portion is 40 ft. and the horizontal part is 95 ft.  It has 10 steel wire radials about 135 feet long laying on top of volcanic soil.  I can only get as high as 40 ft.  Would it help to change the steel wire to copper radials?  I am feeding it with RG8 into a MFJ tuner.  I have quite a bit of room on my property so could play with other wire type of antennas but can't get up more than 40 ft. high at the moment.  Would like to get out better to Asia.  Any suggestions?

Tnx and 73,

Mike  NW7E