I don't have that particular variety but mine is very flexible. So much that wiring must be done more than once on young shoots. Rather unpredictable as to where the thick shoots will pop vrs the majority thin branches. I'm still learning how to deal with it and have no great advice to offer.
In fact I was watching this tread to see others views and advice.
Has anybody had any luck cultivating a bonsai out of them
I'll let you be the judge on that. I've had it only 2 years and may put it back into a pond basket as I was too eager to have it in a pot. Seems to have really slowed it down. Bigger pot or pond basket next year as I need to bulk up the spindly lower branches.
It has been very tolerant of our cold winters with only minimal protection. Mulched under the bench. They do discolor in the winter so don't be as alarmed as I was the first year. Survived single digit temps(F) last year while I was away for a month at a time.
Here is a winter pic of foliage which surprisingly greened right up when spring arrived.