Good too see you back Martin and Gwyn, I hope all is well

Good luck, a daunting task i'm sure.

Congrats mate, it will be a busy and sometimes frustrating time for you in the coming months, but well worth it in the end. I wish you and your fiance all the best

I hope you don't have to sell off any of your camera gear to pay for the wedding, they are horrendously expensive.

I have seen a few sell lately and they generally go for around AU$150

You stop down by turning the aperture ring to your desired aperture. The M series lenses do not have the electrical contacts to allow stopping down via the body. The stop down lever is there to hold the aperture open until you fire off a shot and it thens stop down to the preset aperture.

Simon, setting it up is simple, you will need one of these a reverse coupler, not sure of the filter size of your Sigma 70mm but these are relatively cheap.
[IMG]http://i184.photobucket.com/albums/x261/ClarkyinAus/_IGP1715.jpg[/IMG]
Typical settings I use, would be f16-f22 with your sigma and the reversed lens wide open, and adjust your flash output as required. I found the Pentax 43mm f1.9 and the 50mm f1.7 gave me the best results
Heres some examples
A cigarette lighter striker and a ball point pen nib
[IMG]http://i184.photobucket.com/albums/x261/ClarkyinAus/00K72873.jpg[/IMG]
[IMG]http://i184.photobucket.com/albums/x261/ClarkyinAus/IMGP1903.jpg[/IMG]

Risk of damage to your Sigma is negligble, no more than using a lens in its normal orientation.

You will need plenty of light so a flash is essential, either a ring flash or use your standard flash off camera on a bracket, I made this one myself but now use a ring flash exclusively.
[IMG]http://i184.photobucket.com/albums/x261/ClarkyinAus/IMGP5709.jpg[/IMG]

Heres another option I use with the ring flash set in between the 2 lenses, this exposes the rear element of the revesed lens and as you need to get in close with this setup, risk of damage to the lens is high. So as I stated in the previous post, you can make a filter to cover it by removing the bottom out of a rear lens cap and gluing a 49mm filter into it.
[IMG]http://i184.photobucket.com/albums/x261/ClarkyinAus/IMGP0591.jpg[/IMG]

Using this setup is a lot of trial and error, but well worth it if you want to go beyond 1.1 magnification. cheers

Heres one Don, not far from you either. link

Any Pentax branded flash is safe to use on your Pentax DSLR

Its a Pentax program flash, it has no auto/manual control, I think it was released with the Pentax P series Film camera bodies.

You would be wasting your money IMO, It will fire on your KX but only at full discharge. Pentax only have 2 flashes which will fully support your KX, the AF360FGZ and the AF540FGZ, there is of course the Samsung equivilent which are identical to the Pentax ones I have mentioned. There is one currently for sale in the classifieds for 150quid