Hi Stu,
Camera is a Canon 450D. I use a Lunt variable power eyepiece (bit I think it would work with a Plossl). For the prominences I took a 1/25 sec exposure ISO 200; eyepiece focal length 21.5mm. First, focus the telescope; I wear glasses so I focused with my glasses on. Canon lens set to 24mm and then manually focus the camera on something distant e.g. a far away tree. Then hold the camera right up to eyepiece, look through the view finder and try and to get even illumation of the Sun's disc. Then take the picture.
For the disk I use about 17mm on the Lunt eyepiece and 35mm on the Canon. Same procedure but exposure 1/80sec. The rest is done in Photoshop. There are probably other combinations but this one worked for me. Hope this helps.
regards,
RichardJ