I just finished pulling out the rear shocks last weekend, following the same install info. No problems were encountered. Starting with the rear wheels in the air, the rear shocks in place, the bolts for the lower shock mount and the two upper links were tightened by hand using only my fingers. The car is then lowered & fully loaded by it's own weight, only then, are the bolts torqued down to spec. The trick to this stuff is getting under a fully weighted car to tighten the bolts. The easiest way for me is to lower all 4 car tires down onto 4 equal sized blocks, 12 inches high, and then get under the car to do the work. Yes, all 4 corners /tires are sitting on these bolcks during the procedure. Safety is the 1st concern, so find the right type of bolcks for the job. I use 12 inch wheel cribs, made by RaceRamps for this type of work. Good luck, you can do this, if I could.
Pat- Va MX5
2012 MX5 PRHT GT