Goedjn wrote:


The thought of modifying trusses is not a scary thought to me,
because I have done a lot of work that involved modification
and I have worked with a lot of engineers on what to do, and I
have 30 years of experience in construction. The thought of
advising someone else on doing it sends chills up and down my
spine.

Oh, come on, it's easy. The proper way to modify a truss for
load bearing is to run posts up between the existing trusses,
put beams across just over the top, and build a deck on the
new beams. No problem. You can ADD anything you
want, you just can't take anything out, and nothing that
you add is allowed to touch the existing system.

--Goedjn

Which doesn't solve OP's problem of limited access which is the whole
point of the thread...