Mal,
Sorry to see/ hear your results .
Lets just say i heard once what TCI means but i have not used them so thats not for me to say .
Here is a couple of my thoughts , as i am in Aus just like you . And i have built,worked in auto shops .
I have a foot brake B&M . Cracked old case and no BB core .
I ended up with a Griner RMVB . This trans ran 10.50s behind my 505 . It ran about 9 years with only regular servicing . Only broke 2 front flex bands , swapped to solid band solved that . No other issues. Still on my shelf for a spare .
Current trans has a brake and has gone 10.20s off the brake @4000 trapping just over 7000
This has a billet drum and is set for racing , though i daily drive it . And yes i paid $ for it , similar to importing a CRT .
Both trans have low band apply to help .
Fred @ Protrans here in Sydney built it .
I rang B&M when choosing theirs and they said 600hp is the round about limit as delivered .
I guess its all a pick and a poke . Who will look after you ?

Tex