What are the recommended snipe times (seconds before auction ending) to set for different kinds of connections? (Cable, DSL, etc.)?

In order to change the amount of time prior to auction end that JBidwatcher snipes, you would go to the Configuration Manager and find the 'Sniping' tab. It defaults to 30 seconds, as that's a safe time on all systems. That said, JBidwatcher was originally written when dial-up was significantly more common than other methods, so you can tweak it some.

JBidwatcher does a LOT of internal work to try and understand what your network delay to eBay is, and takes that into account when placing a snipe. So for instance, if you set 10 seconds, and JBidwatcher determines that you have a 2-3 second lag time to eBay, it'll start sending the confirmation form at 12-13 seconds before the auction ends.

Since it logs in and preps the bid at 2 minutes prior to end, and there's only one page that needs to be submitted for the actual bid, this works out pretty well.

Setting the number of seconds from the end to snipe should be how much buffer you want, really. If you're on dial-up, the latency variation is higher, so you want to set your snipe timer higher (like 20-30 seconds), just to absorb that potential variation. If you're on Cable, you have less variation, but still pretty high, so you might want to set your snipe timer to 15-20 seconds. If you're on DSL or an equivalent, it's usually a pretty predictable latency (barring BitTorrent or other bandwidth-hogs), so you can go down to 10-15 seconds. If you're on a corporate network, and it's usually not saturated, you can get away with lower numbers even still.

But fundamentally, JBidwatcher tries REALLY hard to measure your latency, and add that latency in to when it starts the actual snipe.