and you don't seem to want to do this half way

I totally share your appeal for rose gold in a collection. I don't have any since I sold my 1815 several years ago and I must say that I'd like to consider this color for a future new one. The combination with the silvery dial was perfect but I don't know how it looks in the 5196R: you must have a look by yourself and see if it suits you.
Back to your question, I would say that buying two watches at two different moments is a way to multiply the pleasure.
So I'll focus on one and then think about the other one later.
As you'll wear only one of these at a time (!), the process of considering them separetly is maybe a good way to really decide which of the R or G (for each model) is the right one for you.
I'm affraid considering both at the same time may drive you the wrong way.
If it was for me, I'll get the 5196 first and take the "higher" 5130 afterwards.
I think I personally have a slight preference for the 5196G with the 5130R.
The 5130R looked really nice when I saw it, very warm even though not discreet. The G one wasn't to my taste.
As for the 5196G, I like its monochrome aspect.
I don't know how you wear them: which one you use for casual wear, work etc... This might be of importance.
Good luck Tony and please keep us informed of your choices!
Cheers, Mark