not sure how the V-star risers hook on so I never responded (expected staff to answer, but it seems they are busy these days).
If the bolt on like a harley riser (Bolt up through the top tree into the riser) you might try unbolting the riser at the tree, having her sit on the bike and keep rising the height of the bars with everything still hooked up - find the height she wants it and test if everything still works (i.e. no cable blinding, etc.)
There are a number of ways to build a "jig" to help with with getting the bars up and still be solid enough to turn the wheel (i.e. 2 or 3 inch longer bolts and removable spacers such as small pieces of 2x4 )
hope this helps
When workin' on your ride the first tool out of the box should be the manual