"Tom S" wrote:
My current attic situation consists of a 20M dipole, a 30M and two 40M
MicroVerts, and an 80M Hamstick Dipole. Using a homebrew antenna switch, I
can switch between all these and use a tuner in the shack to make everything
look good.

I was thinking of doing the following and am looking for
opinions/sugestions/comments both good and bad.

I would remove all the stuff above

Leave the old antennas up there. That makes it easy and fun to make comparisons
to see how well your new antenna does as compared to the old.

and run ~100 ft of 14G insulated solid
copper house wire around the perimeter of the attic...

This sounds like you almost have a loop. You might consider trying a random
length loop around the perimeter edge of the roof. one big advantage is that it
requires no ground with which to work against. I have about 200' of wire in mine
which peaks at about 20' up. I feed mine with ladder line, but for short runs
coax is ok as the loss would be small. I lucked out because by using a 4:1 balun
it turned out that my TS870's internal tuner is happy with it on all HF bands
except 80 and 160. For those bands an external tuner works fine. It's no DX
antenna, but I never have any trouble making or finishing QSOs. And compared to
my 40M Hamstick attic dipole, the loop gets on average about a 2 s-unit better
report.