I don't do much studio work, but I've got a shoot with an outstanding model next weekend. She's also a photographer who likes film

So, I'm tempted to try a few shots with a 5/4 camera and 150mm lens (which can connect to the studio flash system). Could anyone suggest any obvious errors to avoid? Or, more controversially (for here), is it worth doing? I'll also have an medium format camera which is more obviously suited to studio work, but I'm reluctant to pass up the opportunity to try something a bit different.
And I do know that a longer lens might be better, but I don't have one... yet.
Thanks
Steven