I did some coil spring calcs for a Super using Humbles corner weights that showed that the front struts should be between 73lb/in and 113lb/in for a fast road car. These are based on coil frequencies of 80-100 hz that are 'industry standard' for fast road. My very crude assessment of some standard old springs put them in the 80lb/in range not the 70lb/in suggested but it may be that these are European rates that are typically higher than American rates (did VW have a softer suspension for the US market?)
http://www.germanlook.net/forums/sho...t=10384&page=2
If you have coilovers with 2 1/4" springs you could get progressive rate units wound or a dual rate with a version of stiff helper springs at say 75lb/in plus something over 100lb/in. The final rates of course will be determined by the actual corner weights especially for a Scooby powered bug.
Clive