[luka]

Very nice Chris. Very, very nice.

I remember reading somewhere that fractional ISO numbers should be avoided with DSLRs. In other words you should only be using ISO 400, 800, 1600, 3200 etc.

Also guiding will most likely sort out your blurry subs. The periodicity definitely implies periodic error of some sort. I would not do the strip and grease until you try guiding first.

edit:
You could try the trial version of StarTools or PixInsight for processing. Startools is much cheaper. The only limitation of the trial version is that you cannot save. However, you can use screenshots at the end of processing while trialing it. It is a big learning curve but there are quite a few tutorials on the net.