I could really do with expanding my knowledge as to where to look for other species of butterfly
http://www.ukbutterflies.co.uk/sites.php
This will help you find good sites for the rarer butterflies in your area (where abouts are you?)
Not all species are that easy to find roosting, as some go into trees, and others deep into grass tussocks or undergrowth, but your are right - they make great subjects when docile.
The other conditions to look for, are like today, when the temperature was right on the edge of allowing them to fly. So, when the sun went behind the cloud, they became torpid.
This temperature varies species by species - and some seem to keep going what ever the temperature.
Good luck - (nice images by the way.)