I realise the OP has probably done the job by now, but I'd thought I'd add some pointers for future reference as I've done a fair bit of stills work on films.
Blimps, I've never used one, as shooting during a take is something I'd have no interest in doing. Several reasons, you can get in the way or distract the actors, you may need to be where the camera is if you want to reproduce the shot accurately, you cannot direct the subject, the lighting will be set up for when the film camera is...lots of reasons. So I usually shoot after last take of any set-up. Now some 1st ADs [assistant Directors] will say there's no time to do stills between set ups, there invariably is, but you have to be able to work quickly. Very quickly. If you get this issue, it will indicate you are working with an idiot, who doesn't know the job properly and you will have to work extra hard to get your shots. Sadly these fools also usually think being a 1st AD is a way of becoming a director. The 1st AD's job is more that of a set manager/organiser/logistics, very little to do with film directing and the good ones know that. The 1st AD is your most important friend, so even if they are an idiot try not to piss them off. Though I did tell when to get stuffed once, as he was a particularly talentless numptie.
Shooting stills is a thankless task at best of times, as you are normally completely irrelevant to to the task at hand, i.e. getting the film made, but ironically are of vital importance in getting a film sold. And everyone thinks their job is the most important, when in fact all the jobs are important, even the runners'.
To do a good job , you need to take images that look like how the DoP wants the film to look [much easier with RAW] and the hard bit, to be able tell the story of a scene in single take or even better capture a defining moment/aspect of the film.
I will take actors to one side and do my own set ups if necessary or rejig the blocking of a scene to suit a stills image. A film is made up of shots that are spliced together to tell a story, you have to learn to do it in a single shot.
I suggest reading the script, thoroughly, speak to the director/producer/DoP about look/feel/intent..etc and remember the producer is the boss, not the director. I also always watch the monitor during takes so a to get a sense of how film is being shot and to see what moment if any I need to recreate for stills.
You need to be able to work very long hours, be able to get on with tired and stressed people and be very patient. Hurry up and wait is what you end up doing. Though being an actor is the most boring job, as you have to wait for the rest of us to get setup.
