Trade offs of putting an international master database in us-west-2 I'm hoping this isn't so open ended that it veers towards a "discussion" more than an "answerable" question.

I need to place an RDS Postgres instance in an AWS region that will act as the master DB for writes from all other regions. Those regions will include Australian and European regions, as well as North American. 

My concern is latency on writes. I will use replicas for reads, so that is not so much a concern.

I will be using interregion VPC peering for all regions to be able to communicate with the RDS instance.

I'm thinking that placing the RDS server in us-west-2 as it seems to be in the most "central" spot for all regions of concern.

I understand that the AWS "backbone" is very fast, and perhaps fast enough not for this to be a concern.

Has anyone dealt with this problem and have any metrics or other ways to quantify a decision on where to place this RDS instance?
It's been a while since posting the question, and a comment I made above seems to be helpful despite the fact it's using a quantitative assessment, so I'll post it here as an answer.

As per comment above:

@030 I can offer my experiences since asking the question, albeit it's a subjective view as I have no quantitative data. I can offer that a year and a half later, I haven't regretted my decision putting the master into us-west-2. Our users in any region don't seem to be impacted by having the master in us-west-2, at least from a UX perspective. I suppose at some point it could be worth measuring write times -- but to date I haven't had to. There's no business impact from any latencies due to the location of the master, that we can detect at least, so we're happy here