[c-nsp] BGP - advertising default route to Branch offices

[Yham]

Hello Gentlemen,
I have 100+ branch offices peering BGP with Core and I need to advertise
the default route (only) to them. Core switches are receiving the default
route via eBGP from upstream devices. I can think of two ways to advertise
the default route as follows

1- advertise/pass on the default route that core switches receive from
upstream edge devices. Along with that add a static default route pointing
to null0 with higher administrative distance and redistribute into BGP.
that way if for any reason upstream edge devices stop advertising the
default route, the static default route will kick in.
2 - default-originate command under every BGP neighborship. I have 100+
neighbors so configure this command for all.

Can anyone please tell which is considered a best practice when it comes to
the advertising default route? If any vendor documentation addresses this,
please feel free to share.

Regards