hi Jude,
This may be too late and perhaps you've already resolved your question by now...
but you can change your preferred time settings in 'My Account' > 'Account-Settings' > Account Preferences -- and choose the time setting most convenient for you. If you choose your time according to your own time zone then you will have to calculate and allow for the necessary offset adjustment to target the ebay site time which you wish to post your listing on. If you choose the ebay-site time as your preferred time setting (probably what most people do) then it may be a little easier on the mind to keep start-and-end times straight for your auctions. Some folks prefer one way...others another. Bottom line is that the time zone specification (in account preferences) is the time which is used to 'schedule' a listing submission to ebay.
hope this helps. Zeb
BtW: there are very few things I've found to be truly 'hopeless'. One of those things is trying to accurately forecast the weather for Central-Texas beyond about 4 to 6 hours into the future. Another truly hopeless thing... is my approach-shot from the fairway onto the 8th-hole green at my favorite local Golf-Course.