I am also using a vintage aftermarket floor console I bought in the '90's. I used in my first FA which has the interior as my current one so a good color match. I cut a 1/2" hole through the carpet and pad to allow anchoring with a screw at the center(-ish) of the console. I cut a short length (cant remember how short) of 1/2" pipe to line the hole and provide a solid stop for the bottom of the console. I then drilled a 1/8" hole through the floorpan and ran an interior trim screw in to thread the drilled hole. I used a step bit to drill the hole in the console with a bevel to accept the trim screw (with beveled washer) and match the bevel for a near flush fit. What I very specifically remember is being surprised how long of a screw (and short length of pipe) I needed to reach the floorpan from the bottom of the console. I actually thought about puting the car up on jack stands and use an inspection mirror to make sure I wasn't accidentally anchoring it through the floorpan and to the transmission. It works well, no tipped drinks. The ashtray misses the passenger side cup, but anything taller than a 12oz can in the driver side won't. I use the ashtray to hold phone charger and cord nicely hidden away. The console can also hold six cassettes or eight CDs, a pair of shades in a perfectly shaped tray and coins to pay those tolls (well maybe not enough coins these days). Pics if I can remember.
