four loops two TIU's

Now r u saying u want to run a proto 1 or 2 up or down top or bottom

proto1 and 2 up and down and top and bottom.

I say because you are running variable chennels it would make no difference but that's my guess

We will have to buy it to find out

No problem.  Set all remotes & TIUs to super TIU mode.  You can get away with one TIU if you have a Z4000 with the Z4000 receiver, having that Z4000 outputs feed the FIXED inputs.

 

I have 6 "loops", each on a different channel using 2 TIUs (4 VARIABLE; 2 FIXED).  Any loco, conventional (which includes PS1) or DCS, can run anywhere on the layout.