If you want to choose a moldable, i.e. thermoflex liner with intention to do a bootfitting you need to know that Deeluxe liners are crap and you will need to replace them by something more reliable from Intuintion, Scarpa or Palau.
Tohass actually pick a bigger size, therefore he had this feeling of too much volume after a time...And possibly improper heel fixation. Right?
If thermoflex liner is properly chosen and molded it provides necesssary comfort and dense fixation of everything is needed to be fixed properly. This can be achieved by a bootfitting procedure which involves:
- feet preparation that makes more space for fingers
- heating the liner up to 110-115 degrees C
- entering the boot and knocking to ensure that heel have properly formed place
- staying for a while (25-30 minutes) like heron to make feet expanded a little in the liner to ensure sufficient space.
The size of the boot can be 10-20 mm less than your feet. so if you have 280 mm size feet you can buy 27MP size boot or

if you are crazy enough even 26MP - but keep in mind this would require bootfitting .You can make it in home and repeat if boot not fit well.
Here are few vids with russian sound, but picture should explain.
http://noredirectionallowed/light/starikashka/feet ... kashka.wmv
http://noredirectionallowed/light/starikashka/boot ... nd_out.wmv
If you afraid of scary word "bootfitting" - go for the shop to ensure boot is fitting your feet.