I really dig 35mm in holgas. Don't get an adaptor or anything, just let the cassette flop around - it'll add another dimension of holgesque randomness! Here's an example of how I use it:... I just ordered a Holga and plan to shoot 35mm . ...
I like your photos you shot with real cameras much better. Shooting photos with a toy camera doesn't really lift them from the common. Keep shooting! 🙂