where is the home? CA?

Stud ends ok?

w/o seeing the installation it's hard to give a perfect answer

I'd probably jsut notch/slot the "backside" of the sill & slide it
into place.

If I'm guessing correctly the "tie rod" is part of the hold down
system.

Drill the sill within a foot of the notch (both ways) & install an
epoxy anchored anchor bolt to strengthne the notched sill Use Sika
Sika-dur epoxy

cheers
Bob