I guess you’re packing for an early start to get up Ingleborough in the morning!
It’s not a matter of needing an “Idiots guide”. It’s more that currently, despite being at the bottom of the solar cycle, openings can still occur but this varies from day to day. The VOACAP and similar predictions are very much based on expected averages over complete days. They’re predicting based on statistics rather than live data.
Over the last couple of weeks, we’ve seen DX openings of only 15-30 minutes and they have been on 40m rather than 20m, however since yesterday 20m conditions have improved (probably through the PAE effect). Theses short openings to ZL/VK and even JA are so short that they can’t feature in the VOACAP predictions.
It is really a matter of getting out there and “giving it a try” you might be lucky. Then again there might not be any intercontinental DX but you should bag a few UK/EU S2S contacts.
Whether 17m, 20m or 40m works, will depend a lot upon where the MUF (Maximum usable Frequency) for the UK is check http://www.propquest.co.uk/graphs.php ) - this morning the 3000km MUF shot up to 18MHz soon after dawn but previously it hadn’t been getting up to more than 10MHz until later in the morning (by which time it’s too late for long path). So 40m is the most likely band to work at the moment but 20m is going to be easier with stronger signals if it does work (as some stations use gain antennas on 20m but very few do on 40m).
To come back to your first question - yes around UK dawn and for a couple of hours afterwards, we are talking long path rather than short path propagation to contact ZL/VK.
Depending upon how directional your antenna is (what are you using by the way?) - it will need to be in a slightly different position for ZL, Eastern VK states, Western Australia and Japan / Taiwan.