Tip O'Neil 1887
Barry Bonds 2004

Both in Yankee Stadium 1B/ +1 HR LF/+3 HR RF/+4

Bats: O'Neil (right) Bonds (left) slight advantage Bonds (since all hitters are pull hitters in WIS)
AVG#: O'Neil (429) Bonds (362) heavy advantage O'Neil
AVG+ O'Neill (160) Bonds (138) moderate advantage O'Neil
HR/100AB O'Neil (2.7) Bonds (12) heavy advantage Bonds
HR/100AB# O'Neil (4) Bonds (9) draw (since O'Neil's adjusted power comes up by 50%, while Bonds is down by 25%)

I'm about to start a $255M league with these guys as 1-2 in my line-up. Who hits more HR at home?

Both never hit homers for me.
My guess it'll be
Bonds - 25
O'Neill - 12

I've gotten as many as 30+ from O'Neill but it was in a lower cap and home was Altlanta Fulton or one of the Wrigley Fields.
Contrast that with rarely getting more than 20-25 from Bonds. I think it'll be close.