Wishing to attach some [SWL 2000kg] 4-part fiddle blocks possibly mid-boom
[aluminum], probably using either 1/2 or 9/16" nylon lines, what would be
the proper technique to insure sturdy attachment and avoiding interference
with boom function ?

Mobile attachment on boom would be even more desirable if not fraught with
various perils :-)

Appreciatively,

Courtney