You can get IQ routes and ALG to work on a 1GB device, as long as:
1) you have the compatible navcore and
2) as long as the map fits, for eg. under about 900MB.
You have 1 out of 2, as you have the correct navcore. But the United States IQ map is too large for your device. Therefore the ONLY United States map you can use on your 1GB device is United_States_905_4853.
Don't worry about all the other maps you mentioned, as there is no meta currently available for them, and they are practically the same maps anyway. They are named differently for different models. The slight difference in size could be due to the number or POI - nothing really major.