The difference in playing hard tension over regular nylon strings is that it gives you more snap to the notes and more volume. With regard to playability, they're still considerably easier than steel strings, that is to say, they're under far less tension and shouldn't strain your fingers.
The usual complaint with switching to nylon/classical guitar is the neck width causing hand strain but you seem to have crossed that bridge.
The more accomplished any of us become as guitarists, the more economical with hand-movement we become (much to the annoyance of new players who want to study other guitarists fingerings) and I get the impression you're an advanced player, so I suspect that this obstacle will be overcome by you in terms of deciding wether to go round it or over it. No question that you won't put it behind you.
I'm a big Django fan myself and even with the full use of all my fingers...........well you know the rest!
C-flat.