I did it on my own, but depending on the weight/centre of gravity of your spkrs, that extra person could be invaluable.
I believe it's essential to have a thin shelf on the floor to put the spkrs/Rollerblocks on (Svelte Shelf ideal, and this is indeed how Symposium advise, 2 layers of isolation as result), so that you can move the whole shelf/spkr as a unit re toe in etc. But might not be poss if the weight starts to exceed 120-150kg (my Zus are under 100kg so I'm ok here).
Remove one spike at a time, insert either the whole Rollerblock Jnr item (so that in sequence top to bottom: spkr-top cup-ball bearing-bottom cup-shelf-floor) under one outermost edge of the bottom of the spkr, or "half" (exclude bottom cup). Carefully prop the spkr on this single support, and then replace the remaining three spikes in sequence, Rollerblocks one spike at a time. Being extremely careful not to asymetrically load the Rollerblocks so not to have the ball bearings go flying (more an issue in my set up where I'm not using the bottom cup).
You'll know you've got it right when the spkr sits there totally stable, but a shove to the side sets up a short lived wobble - only to be done on an alcohol free day
!