[raymo]

O.K. Firstly, I disagree with Anthony; I suggest you get your procedure
working well, and explore the limits of your unmodded camera before
laying out hundreds of dollars on a modded camera, because if you get
hooked into astrophotography, you might well decide to go for a much more sensitive dedicated astro camera.
What is the focal length of your scope, and what mount do you have?
You will obviously get star trailing if your PA is not good enough, but should never get any jerkiness. As an example a 1000mm focal length scope at
prime focus, well polar aligned, should give all good subs at 30 secs, and
an acceptable percentage of useable subs at 45 secs, and a occasional
subs at 60secs or even a bit longer.
I wouldn't waste time on darks until you are producing some reasonable
images, and as Anthony said go out to around 1600 ISO. which is the so
called sweet spot for many DSLRs. I light pollution filter can help, but then
you will have the job of removing the colour cast introduced by the filter.
Further to the modded camera, it is only the fainter red nebulosity that
doesn't show well in an unmodded camera, all the other colours are unaffected.
Longer subs can overcome that to a degree. I have managed without a modded camera for many years.
raymo