New Englanders have experience working with ledge.
As a recently transplanted Vermontah, I'd suggest
looking at renting large reciprocating drills, and
pressure-grouting the anchors into the holes.
For professional advice, I suggest you contact KC1XX.
Matt knows how to do it.
No idea whether you'll find someone on the left coast who
knows from this technique.
Essex Junction, VT
ps: with appologies to all real Vermontahs, who know I'm
really nothing but a flatlandah, who couldn't hack more
than 8 wintahs!
color me happy to be back on the coastal plane!~
I'll come visit the snow, thanks.