Same here... it is really difficult. The problem is that the crimping tool is also designed so that everything fits in perfectly when you're finished and it holds solidly. Without it, they can come out or loose.
I would recommend getting some that are already crimped. They're not all that expensive at all at 10 for $2, if you don't mind waiting for them to come out of Hong Kong (usually only takes about 10 days from HobbyKing).
Brandon
My bad... I think 5 for $2. I was thinking they had dual female jst cables for 3s batteries, which you could effectively cut in half, but they don't. At least not that I've been able to find yet. Sorry about that! I truly believe I do need to quit today... lol.
Brandon