i have been struggling with getting my soundpost back into position, as it took a trip south over the winter. The position on the back is marked, but the underside of the top is not. Any tips on ensuring the post is standing straight? Considered inserting a grabber tool with a piece of thread to and hold it next to the post to allow gravity to do its thing, but alas, the instrument has quite a pronounced roundness to the back, so not 100% sure when it is sitting completely flat... Any suggestions??