Where to create new fields for SFDC PersonAccount Contact or Account?

[DYerger]

I read through the PersonAccount threads and got some good info, but its still not clear to me if new fields for a person account should be added to the Contact component or the Account component of the PersonAccount on SFDC. Its also not clear to me if we need to recreate custom fields on the Contact component  that were added to the Account component previous to acquiring Marketo. Does anyone have any insight on how to expose new and existing custom fields on the PersonAccount to Marketo Sync?

[Chris_Willis1]

Depends.  Do these fields need to be editable from Marketo?

If yes, place them on the contact.

If no, then you can place them either on the account or the contact (wherever it logistically makes sense).

Marketo only has update rights in SFDC for the Contact object and can only read the Account.  

[Phillip_Wild]

So I would be interested to know how this works too. In past lives, we used to have access to Account fields directly, but my memory is that Marketo Support did something custom to allow us to write to Account fields (for person accounts). 

There's a duplicate Contact behind every Person Account too, so maybe we were simply writing to the Contact and it flows through automatically to the Person Account from there?

[Veronica_Lazar1]

I work with Person Accounts in our SFDC setup and normally I use the contact fields in the smart lists.  If we write in any contact fields we do have automation on SFDC side that copy from contact to account. 
In order to give Marketo visibility over the Account fields work with your SFDC admin to give the fields read access, in SFDC.