Well, you are replying to an old post dated back in 2013, but, DO NOT downgrade the machine with 32-bit version. But, you can buy the digital download version of Windows 10 32-bit from Microsoft but you will need the drivers as well.
You are talking about a big pain in the tail section to do and you actually ruin the tablet in the long run.
Your best bet in your circumstance is one of two paths. 1. You can remove all software relating to the camera from the tablet and then just plug in the camera and be able to move the pictures/videos over from the camera via the file manager since the tablet
will look at the camera as an external drive. Or, 2. You can get an ATOM based Windows 10 tablet which runs the 32-bit version of Windows 10 and use it instead and use the Surface tablet for post-production.
There is a third method of using Hyper-V or other virtual machine software and install Windows 10 32-bit along with your current system but you run out of disk space at that point in doing that.
Getting the 32-bit ATOM based tablet is the better bet in the long run and would recommend the Asus T102 (I have one) and it gets 12 hours of battery life plus it comes with a keyboard/touchpad cover and pen. It also has a full powered USB port as well
and the 128GB model is $400. That way, you have a second machine in the mix and then later, use the higher performing Surface tablet for your post-production work. In that case, you can transfer your media via a micro-SD card between the two machines.