Since there doesnt seem to be info on this anywhere I wanted to start a thread with the torp layouts all nations ss.  Please feel free to correct or add info.  This is what I have played or been told from other SS drivers.

IJN

Tier 5 = 4 forward

Tier 7 = 4 forward 2 rear

Tier 8 = 6 forward

Tier 9 = 4 forward 2 rear

Tier 11 = 8 forward  

KM

Tier 5 = 3 forward

Tier 6 = 4 forward 2 rear

Tier 7 = 4 forward 1 rear

Tier 8 = 4 forward 1 rear

Tier 9 = 4 forward 1 rear 

Tier 10 = 4 forward 2 rear 

Tier 11 = 6 forward 

US

Tier 5 = 4 forward

Tier 7 = 4 forward 2 rear 

Tier 8 = 4 forward 2 rear 

Tier 9 = 4 forward 2 rear 

Tier 11 = 6 forward 4 rear

UK

Tier 5 = 4 forward

Tier 7 = 6 forward

Tier 8 = 6 forward 

Tier 9 = 6 forward 2 rear

Tier 11 = 6 forward 4 rear