Hi after installing the cap can I lay the bottle flat, back in my wine cooler? Ie will it leak? Thanks all!

We do this all the time and have never had one leak. Simply put the stopper in the bottle and pump the Vacu Vin until it clicks and you're all set. We have even left it this way for four weeks and it has held.

How long does this preserve wines?

In my experience, it actually depends on the amount of wine left in the bottle. Amazing because one bottle of Chilean bottle was still drinkable, didn't taste like vinegar at all after 6 days. That bottle was more than half full when I left it in the ref using the vacu vin. However, one bottle of Australian CabSav didn't taste so well anymore after 4 days when I left it w/ just a third of wine in the bottle.

Can you tell from just looking at this when it is/when it is NOT vacuum'ed?

No, you can't tell by looking at it. However there is an audible clicking noise when the air is out of the bottle, so that's how you can tell the air is vacuumed out. The point of it becoming harder to pump varies based on the amount of wine/air left in the bottle. It isn't difficult, though, just provides a bit more resistance.

Will this work with a bottle of bourbon or scotch?

As others have mentioned, YES!, the stoppers definitely WILL seal/vacuum most ANY wine, 750L/Qt.-sized alcohol, 1.5 Ltr soda bottles, and/or so many OTHER glass bottles typically manufactured with the same/fairly common standard-sized opening/inside diameter of approx 3/4-inch... VacuVin does NOT recommend using the stoppers on opened bottles of carbonated/sparkling beverages (especially something like Champagne, for example...), but I've used it MANY times to seal/store a half-finished bottle of beer, carbonated wine cooler, etc, out in my garage 'fridge, and those drinks STILL had their carbonation even after 3 or 4 days! Lastly, I also discovered that the VacuVin hand pump can be used/works perfectly on any Reynolds/Handi/Zip-Loc etc-type Freezer bags that have that blue, circular-type Air Valve on them to remove air from the storage bag before freezing!