Seems to me that the original problem has three sets of issues.  The first
is an altitude challenged operator, like me.  The second is lack of the
Ahnold-the-terminator physique.  The third is a larger-than-life additional
mass on the top.

For the first issue, a pause and reflect solution involving one or two small
braces and a step device works for some.  A short piece of 1" pvc with
rubber crutch tips on each end is the prop that holds up the top while you
put the step in place.  A second similar but longer brace can then be used
for the next 'step'.  These devices exclusive of the step store easily.  If
you lift the top directly by pushing on the top itself it is easier for step
one.  Ratchet effect could be considered here.

For the second issue, two folks are stronger than one.  Lifting power can be
increased through training of course but not in the short run.  For those
times when a second lifter is not available see below.

For the third issue, partially unload the top to reduce the force needed to
raise it.  Trades time for creature comforts..

Or you could sleep downstairs.

There are advantages to being altitude challenged.  With nice cushy rugs on
the floor, using a supplicant position to do things (on your knees) works
really well even with the top down.

For folks the size of Warren 6.5'+ it takes some adjusting for folks like me
5.5'+ it's easier.  Gracefully hopping into the attic takes a step on the
ever-present cooler, a step on the sink corner and there you are.

Pensioner  (for short guys the snow is always just a little deeper)