Any steam iron can develop incontinence. Having said that, I do prefer the steam function. I use an arm sleeve ham and place my seam over it then iron. No wrinkles or distortions as the fabric automatically is wrinkle free this way.

As for a clapper - even though it wasn't in your question - I use the bottom of a point shaper/tailor's board I bought at an estate sale. I would think any finished piece of wood would do.

If you have a heavy bacon press it will work for a clapper for block seams. Just be sure it's grease free!