Is your name David by any chance???
and to your question....
Hot water extraction all the way! It might shrink if its over 20 years old or a belgian wilton or axminster or a sisal or a seagrass... badley fitted etc
Is the carpet on underlay? a gripper??
If you are worried about shrikage, just give it a light pre-spraying, loads of dry strokes and use air movers are well as opening the windows if its a nice warm, drying type day OR close the windows and turn the heating on if its damp outside!
Use hot water, its hot water extraction after all..
How much do you usual charge? charge that.
No girls, just hairy men with tackle!
Tony