Terrifying job!
I was recently advised to obtain spring compressors which include safety straps. Having never seen these I can't comment on how well they work, but they certainly sound like a bloody good idea.
I found it very difficult to remove the front springs way back when I dismantled two cars in order to undertake a comprehensive rebuild of one of them. I had a lot of trouble getting spring compressors to fit between the spring and the upper inner wheelwell, and the compressors always seemed to be about to twist off the coil with each further fiddly and small turn of the spanner/socket. I remember reading on a previous version of this forum back then about the method using threaded rod from inside the car. It sounds like the smartest option to me, if more time consuming. I also seem to remember having been advised that relying on the bell shaped spring cup to take the strain when using retaining rods as per the workshop manual was foolhardy, as the cup can apparently corrode from the reverse side, unseen, and give up the ghost suddenly with obviously dangerous consequences. If you struggle from in the wheelarch you're simply not going to be able to retract your head faster than a loaded spring and associated tools can come flying unstuck.
Good luck, take care!