Good guess. Believe me, I was very tempted to do that and then wrap the boot with tape, but that never turns out well. Eventually the tape gives way and the split shows.
So, to get the boot on, I was able to slide the blue connector and the white connector through the boot by turning them sideways and sliding/pushing them through. I also applied a little heat with a hair dryer to make the rubber a bit more pliable during this operation. At this point, the number of wires now passing through the boot will not let the other large connectors fit through the hole. So, next I put all the smaller connector wires through the boot which left just the large black connector and large green connector remaining. At this point, starting with the black connector, I removed each wired terminal from the connector housing and passed the wire through the boot, then re-inserted each wire terminal back into the connector housing. I did this for all the wires starting with the black connector then finishing up with the green. the last few wires of the green connector were pretty snug passing through the boot, but eventually I got them all through. Such a pain, but much better than cutting the boot.
I know, It looks so much better with the black. There is also some small writing in gold on the wires but I will rotate the wires so they are on the underside and not highly visible. Thanks!