Thanks for that (fixed the link up a bit). Useful if you've done 2006 and/or 2007 GVBR.
The young fella and I rode 20km and climbed over 1000m on Monday. So we should be OK then?
You need to be careful, averages can be misleading. Climbing 1000m in 20km is an average of 5%, which is a fairly moderate (main road) type of incline. You need to consider what gear you were in and whether you had any lower gears in reserve. For example, how would you go if you came upon a section that was 8% or even 10% gradient? Sometimes short sharp sections are encountered on big rides. There was one between Whitfield and Mansfield in 2006 not to mention Tasmania.
Having said that I don't believe Lavers Hill will present a major challenge if you have climbed 1000m at 5%. I drove the course back in July and gathered the impression, as best you can from the driver's seat, that the gradient was in the vicinity of 6% at the base but then settled down to a lesser gradient with several respite sections, where it was flat or mildly undulating. The last time the GVBR visited Lavers Hill we rode up from Gellibrand in wet and cold conditions. Coming up from that side was not particularly remarkable, the temperature at the summit (and on the descent) being the main topic of discussion after the ride.