'91 dash tweeter install

[FastCAD]

Hello all; has anyone mounted audio tweeters in the dash top corner openings of the '91 sho? My question is how did you mount the tweeter inside the opening? It seems that the base of the opening is only paper?? Also, how should the bass speakers mounted in the trunk under the rear corner speakers on top of the rear tray be wired to the amp delete system harness?
Thanks for any help,
Joe
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