It wasn't always so clear cut. I've only studied one Union regiment in detail and it was formed in late 1863 early 1864 but the rule of thumb for it was if you recruited 42 men you could earn a captaincy, 30 men for 1st lieutenant and 20 men for 2nd lieutenant. But some successful recruiters were never commissioned and some men were commissioned who were not recruiters at all. Commissions were not automatic, they had to come from the Governor. I did a quick search for Shale in the St. Joseph Morning Herald and only found an article where his death is mentioned, no articles about him recruiting in the area. You can find this newspaper online at the Missouri Digital Newspaper Project of the State Historical Society of Missouri.
If you really want to pursue whether Shale ever recruited, the regimental files at the Missouri State Archives would be the best source. The finding aid for infantry units is at this link https://www.sos.mo.gov/CMSImages/Archives/resources/findingaids/rg133.21.pdf
There are 64 folders for the 33rd Regiment. If you narrow your request to certain folders (like those for company H and the regiment as a whole), an archivist will give you a page count and ask for payment, then they will send the pages to you once they receive payment. You might find something that way or come up empty. You can initiate a request by emailing email@example.com I've had nothing but good service from them and their regimental files contain much interesting material not found in the compiled military records.
Hope this helps, Tom Jones