The other option instead of DSS is to get Nebulosity 2 and a DSUB and cable from Shoestring Astronomy. Your DSLR will automatically take anything up to 30 seconds in bulb exposure mode. Anything more and you need the shutter control program. You plug the DSUB into the computer using the pin on your DSLR and USB on your computer. The second cable goes from the regular camera female to USB female on computer. If you want you can get an adapter that's ac/dc connect in the battery area and plug in so you don't have to worry about running out of battery power or card since you're saving on the hard drive. You can frame and focus using 1 to 5 second shots, abort and do a preview at whatever time you want - say 2 minutes. If it looks good you call whatever shot you're taking M42 series and 100 exposures. It will take the 100 exposures at 2m each. You can stack as you go or leave them as fits files so you can add flats or dark as you wish. I've tried DSS but prefer this to EOS utility.
Have to wait and see how your's turns out. I am actually gonna give DSLR another try. If that turns out poorly then I will revisit the adapter. But of course, in the meanwhile, if Charlie gets his, and posts something incredible all bets might be off!