I don't know what car/engine you have
-- you really should add that to your signature for the sake of accuracy/clarity in future posts.
I used the loaner tool from the auto parts store (like the one in the image below). It worked perfectly. I did bend the center tines in (silver part, not the metal hook part) very slightly to allow them to seat better on the springs. You'll see what I mean when you have the tool.
On my 102 engine (4 cyl) I was able to access all the springs very easily. I presume those who had trouble with the rear-most springs have the 103/6 cylinder?
I highly recommend "the rope trick" vs compressed air to hold the valves. Mine required a significant smack with a hammer, using a long socket extension for a drift. If compressed air was all that was holding them, I'm quite certain that I would have dropped some into the cylinders.
That was my experience. Good luck, it is actually an easy job. Once you get into it, you'll wonder why you put it off so long.