I am not sure myself what it is I am actually asking. As always will keep short.
But let's give it a go.
Hypothetical scenario:
$200k in cash
First home buyer.
Buy house for $450k.
Walk into bank to initiate master slave relationship.
Bank be like "here bro have $450k"
Now What do I do?
Do I be like
"Nah bro I only need to borrow $250k, with $200k deposit"
Or
"Yea bro give me $450k and here's $200k in offset account"
Edit 1: If someone went with option 2, would they tell the Master (bank/load provider) they are going to put $200k in the offset tomorrow? or keep that information sealed
20% deposit ($90k) so you don't have to pay LMI (Lenders Mortgage Insurance).
Borrow 80% ($360k).. put remaining in an offset ($110k).