I've had cause to have the centre stand off a couple of times recently and the springs are pretty fierce.
With awful memories of wrestling with stand springs (fitting the bloody thing for a start) and watching a mate fix his stand by the side of the road in Tiblisi made me look for a solution.
Well here it is:
F'ing marvelous and only a few pounds. Makes the job an absolute
breeze.
Here's one like it (I can't remember which seller I got mine off):
http://www.ebay.co.uk/itm/291173926311