I Have not been in here for a bit but this might help. As you are starting with Raw images chances are that they are 16 bits per channel reducing to 8 bits will save a lot of ram. Unless the images are badly exposed and you need the 16 bits of space to correct them nothing will be lost by changing to 8 bits after all its what the monitor and printer use.

The next bit is print resolution. 200 ppi means the smallest detail in the image will be 1/200th of an inch If your eyes can see better than that by all means use more res. otherwise its just using more memory

Producing a smaller image and then resizing up by means of inpolaration, the art of manufacturing pixels by guess work, will produce low quality.

Trev