We made a free tool for you. You can download and print this paper layout map as a helpful aid to find out which snaredrum lugs and tensionrods fit to your drumshell. Just fold it on the depth from up to 8" and compare the lug holecenter to the length of the tensionrods (measured without head). On the other side is the snarebed tool Gerd made. You can stick it on the shell and then grind and sandpaper the snarebed like the shape. You can find all in one PDF file on our tipps and tricks page: https://stdrums.com/en/i/tips-and-tricks