Yes, use a TC case, you are safe to use WU with him, he is a trusted seller/dealer.
TC doesn't use ETA though, he has his owner movement supplier.
A TC Sub is $585 I think
New ETA movement will be $225 ish
Gen dial $400
Gen crystal $250
Gen insert $150
Gen crown $100
So total about $1700, you will probably be able to sell the TC dial, insert, movement, crystal for about $300 but need someone to put it all together which i guess would be about $150.
So total about $1500 using decent correct model gen parts.
It will be cheaper if you use worn or scratched parts that won't look as good.