After what seemed an eternity my Dimpling Pliers arrived today from US supplier, Aircraft Tool Supply (ATS). I've decided I'm going to use these guys for all future tooling requirements. I've found them to have reasonable pricing on tools, a professional approach to all dealings, and offer "half-reasonable" rates for freight (although I'm still not happy about how much it costs to get anything sent to us out here in the colonies).
Tonight I just spent some time getting to know my new dimpling friend. I found that I still had to grind a couple millimetres off the bottom jaw of the pliers so I could get in close enough to the web (and not distort the flange with each dimple), but once I got it set up it worked a treat.
I only did enough tonight to give myself confidence that I now have the right tool for the job, and will get into it in a proper way tomorrow.
That's better. Suprising what you can do with the right tools!