If your goal is only to load the magazine in the easiest and most efficient way, this $5 tool works perfectly:
https://www.midwayusa.com/product/87...-22-long-rifle
And makes cleaning the upper section of the magazine easy.
My '38 Mauser shooter has a finicky hold-open that only works reliably with one magazine that has a stronger spring installed by G.T. Using just my thumb, it's painful to load rounds 5 through 8. This tool makes my range life much easier.
In general, Luger magazine springs seem noticiably stronger than those used in other pistols from that time. My guess is the springs are stronger because they need to be to insure reliable feeding, due to the steeper angle of the Luger grip vs. its contemporaries.