My first Quad Mod was along the lines you suggest, Tsushima1. I simply removed the existing lines from the WBT connectors and insulated the ends. Then I routed new lines (15 AWG silver coated copper) from the connectors to the downstream side of the signal shaping network (cap and resistors). Then I put my caps and resistors in another box with WBT connectors on both sides, et voila! I connected amps to my new box, and the new box to the Quads.
To restore to original condition, one need only remove the new wiring from the WBT's, and re-solder the old, which you have carefully preserved in the black electronics box.
I found that the more film and foil, and the less metallized, the better. Changing to Plitron transformers was better. But, be careful, please. Since you are talking about modification, I assume that you know about the required safety practices. Otherwise, I suggest leaving it to a tech.
To restore to original condition, one need only remove the new wiring from the WBT's, and re-solder the old, which you have carefully preserved in the black electronics box.
I found that the more film and foil, and the less metallized, the better. Changing to Plitron transformers was better. But, be careful, please. Since you are talking about modification, I assume that you know about the required safety practices. Otherwise, I suggest leaving it to a tech.