Mike,
Brian Marelli once told me that the distance between the bottom of the front crossmember and the road should be about 5 inches. This was for a 411, but I doubt this would be very different for a 409. Of course the tyres you have on the car can make a difference.
My 411 sat a little high and I discovered that someone had fitted longer than original springs, probably to compensate for the disintegration of the
"distance piece" PN 407-1-23117 .
If you decide to return your Bristol to it's former glory by fitting new springs and distance pieces, I would also suggest that you fit the
spring isolator and retainer which were fitted to the 411, this should extend the life of the distance piece.
Regards,
Kevin
Edit/PS: to avoid any confusion
these are the parts I am talking about - the top three parts in the picture, the bottom one goes at the bottom of the spring.