How do details vary from different sizes?

Aubusson rugs Aubusson tapestries  
Aubusson pillows and cushions

Details in different sizes

For aubusson rugs and needlepoint rugs

Are smaller sizes carry the same details as bigger sizes do?

The answer is "NO".

The following sizes carry the same details which are standard full details in one particular pattern,
6'x9' (183x274cm)
8'x10' (244x305cm)
9'x12' (274x366cm)

Smaller sizes carry less details than the above sizes due to less areas.  Bigger sizes carry more details than the above sizes as there are more areas needing additional details to fill in.

Anyway, the bigger the size is, the more beautiful the rug would be as there are more details to enrich the pattern and all details have enough room to breathe comfortably.:)

Of course this does not mean smaller sizes are not good.   Sizes such as 3x5,4x6 usually are purchased a lot as samples for clients to show samples to their customers since they are easy to carry and are enough to show the quality and craftsmanship.  And small areas do need small rugs of course.:).