180g fill rug (or what would be best) for mid-season (autumn/heading into winter)?

So now it's May and well into autumn and my horse (lives outside, if this isn't the norm for someone) is at the point where he needs to go into a different rug (currently in an unlined waterproof canvas but this past week the temperature has dropped, especially at night) but I don't want to put his heavy winter rug on yet (which I'm still not sure on the fill of but it's a heavier rug for winter).

I'm looking at a rug somewhere between 180g and 220g fill (I've got a few options) and was at the horse shop today and they also thought up to about 220g would be good for this time of year, but I was wondering what others thought. I'm trying to go light enough for there to still be a difference when it gets much colder in winter and he goes into his winter rug, but enough of a difference to make him warmer now and have this rug as an inbetween rug, for autumn/early spring or any days in the warmer months when the weather turns terrible and he needs something a bit warmer and drier for a day or two (we had a freak storm at the beginning of March where we had to race around and find all their warm covers).

This is currently what I'm looking at as the lightest option: http://www.thathorse.com/listing/rugs-and-covers/s...

But I'm also happy to go a little bit heavier with something like this: http://www.thathorse.com/listing/rugs-and-covers/w...

, this: http://www.thathorse.com/listing/rugs-and-covers/w...

or this: http://www.thathorse.com/listing/rugs-and-covers/w...

If anyone has an idea of what would be better that would be awesome. The last three are all the same fill and pretty similar and I can't see any major differences in features that would make one better, but I haven't been in "this part" of horses long (bought my boy as my first horse last July - and whilst I've had years of horse experience picking rugs was never one of them! Oh the things you learn when it becomes all your responsibility...).

Thanks in advance.