Phil,
I haven't been following your posts about the vertical trials and tribulations, but yours are typical results. I feel your pain...
For "local" east coast work on 75M and 40M, it is hard to beat a dipole at 1/4 wave high. (even a shorty dipole)
If you do go with the inverted L, be sure it is way in the clear, away from buildings, towers, power lines, etc. (To reduce both pattern distortion/absorption and RFI) A horizontal dipole is more immune to these objects due to its higher take-off angle and horizontal polarization. It is less Earth ground dependent too. The higher takeoff angle is also better suited to closer in AMer population concentration on the east coast.
T