Niki,
I think taking only one spring out might make it more difficult, causing it to kick over to one side.
The best way would be to find some 'softer' springs. The hard part is finding them.
For work purposes I've had custom springs manufactured, and it was not that expensive for the large batches (100 springs -- $200), but I don't know how cost effective that would be on a real small run.
You may be able to find an industrial supply company/catalog that has something you could use. I would NOT cut your springs, since that will only reduce their tension over part of their range, and you can't go back should you cut too short.....
The only other thing I could think of is for you to use your ingenuity to engineer your own version of the WoodRat plunge bar.
http://woodrat.com/plungebars.html
Hope this helps,