Answer is: No one knows. Our allocation is also about 75/25, but almost all of the equity is in VTWAX.
Here is Kenneth French on home country bias: French on International: https://famafrench.dimensional.com/v...home-bias.aspx
and here is Vanguard on the subject: https://www.vanguard.com/pdf/ISGGEB.pdf
Personally, I don't try to pick sectors but if I were to do it I would not screw around with allocations less than 5 or 10% of my equity tranche. Tiny allocations will not have useful effect on the total IMO.
Our fixed income portion is around 90% TIPS. I think that is a "Go big or go home." investment. A tiny TIPS allocation provides no meaningful inflation to a portfolio, so why bother?