help. heater core routing

[bimmer_adam69]

i looked up frank m's writeup,

couple q's,
-the inlet and outlet lines iof the heater core, does it matter which one is which???
can i use a t fitting between the t-stat housing and the expansion tank and run a line back to one of the inlets??? and if so, which inlet, upper or lower???? this is the setup ive fitted and just wanted to check with you guys before i go busting a heater core(potentially)

[E30SPDFRK]

Bottom is the inlet I believe. I'll check to make sure in the morning.

Edit: I think it was speedhop that had a drawing of where everything goes

[E30SPDFRK]

It was FrankM's drawing