Another article went up about how great a trade target Smith is:
https://blogs.fangraphs.com/the-best-reliever-on-the-trade-market/
Unfortunately, since FG is going down the crapper with their hiring of sub-par fluff writers to replace the talent they lost to MLB teams, the author didn't take the time to go all the way with the article and analyze the returns for those BP rentals.
So I guess that's up to us. Here are the FVs of the players at the time of the trade (as best I could determine):
Zack Britton 2018 - Dillon Tate 40+, Josh Rogers 40, Cody Carroll 40
Mark Melancon 2016 - Felipe Vazquez (probably a 45 as a potential impact BP arm with some MLB IP), Taylor Hearn 40
Addison Reed 2017 - Gerson Bautista 40, Jamie Callahan 40, and Stephen Nogosek NA
Jeurys Familia 2018 - Will Toffey 40, Bobby Wahl 40, $1M international pool money
Joakim Soria 2018 - Kodi Medeiros 40, Wilber Perez NA (young arm from the DSL)
Anthony Swarzak 2017 - Ryan Cordell 45
Aroldis Chapman 2016 - Gleyber Torres 60, Adam Warren NA (MLB arm), Billy McKinney 40, Rashad Crawford NA
The Chapman insanity aside, we see these top rental BP arms seems to cost 2-3 40s, with maybe a 45 in there to push the package over the top.
The price for Smith is likely going to be the same. The Braves have a ton of 40/45s for the Giants to take the 2-3 they want:
Kyle Muller 45+
Shea Langeliers 45
Joey Wentz 45
Alex Jackson 40+
Kolby Allard 40+
Greyson Jenista 40+
Braden Shewmake 40
Freddy Tarnok 40
Huascar Ynoa 40
Michael Harris 40
Tristan Beck 40
Tucker Davidson 40
Victor Vodnik 40
Vaughn Grissom 40
Daysbel Hernandez 40
Patrick Weigel 40
Jasseel De La Cruz 40
CJ Alexander 40
Josh Graham 40
Lango probably isn't going anywhere, but I would be fine with any 3 of those 40s (though Vodnik would hurt).
If Muller or Wentz go that would be pretty much the whole package.