In uncompressed wav form, the six channels of the 5.1 mix are a total of about 3.9 gigabytes in size. Depending on the format and settings, lossless compression can probably reduce this to somewhere around 2 to 2.5 gb.

As with other lossless codecs, DTS-HD MA uses a variable bitrate, so louder parts of the track will take up more bandwidth than quieter sections. The LFE channel is mostly silence, so it compresses more easily than the rest. The inclusion of a 1509 kbps core track may reduce the efficiency somewhat, resulting in a slightly larger file size. It's difficult to say for sure how it will turn out until it is actually encoded, but at any rate it will definitely be rather smaller in size than the uncompressed source files, which are in 16-bit, 48 khz resolution. 16-bit seems to compress a lot better than 24, from what I've seen.