I must confess that I am mostly with Frank & Quixotic on this and was largely using toe clips before. Though I have now moved onto flat pedals with pins, which are better still.
When I first started out in the late 70s toe clips where exotic pieces of equipment mostly used by racing cyclists. The latter were a rare and elusive breed who wore cleats. And if you look at the pictures in Rough Stuff Fellowship archive or the CTC Cycling Special video then few of them use toe clips and not many are wearing what we then called cycling shoes.
However, one of the reasons I finally shifted to "clipless" was because it's hard to get decent cycling shoes that aren't designed for SPD use only. This being one of the reasons I tried using SPDS them on my new bike.
It may well have to do with confidence , and as some of you have suggested, I may need a different cleat. I have, I believe, kept the springs at their lowest tension. Also wondering if a pair with a platform, eg the 530s of the M324 might be a better choice.
So let's persevere for a while yet.