I always carry an internal trowel although preferring to work opposites.
On the subject of the adjustable internal trowels, well I'm like a few others on here and can't resist a new tool (no comments please Spunky) so bought one, to save someone out there wasting their money if they want the one I bought they can have it for free as long as once they realise how k-rap it is they pass it on free of charge (like a chain letter), thus saving plasterers all over from wasting their beer money.