So here's a data point. After 7.6 hours, basically the same amount of the it takes the mini to download and validate 100% of the chain, the above change has resulted in the mini downloading and validating 15% of the chain, and this will likely slow dramatically as the point table grows.
95% of all time is spend storing blocks, and 92% is spent checking the point table for existence. Of that time, basically all of it is spent paging.