I have never really understood the boundary between "complications" and "grand complications" in Patek's catalogue, specially with Perpetual Calendars. Only explanation I can find is marketing and price positioning...
To me, an Annual Calendar - Monocounter Flyback Chronograph with Power Reserve indicator is more complicated than a Perpetual Calendar.
That said, I do love both references, 5960 and 5140, specially the two versions you're considering. Very different watches in all aspects (complication, look, wearability...), and my answer here (ideally) would be to get both 😊
If I had to choose under a gun, and based on your pictures, I would go ahead with the trade and get that blue 5140P, which looks awesome on your wrist. And although I own that exact 5960P and don't plan to get rid of it anytime soon, I am more and more into flatter watches nowadays based on comfort.
All the best with your decision and please keep is posted! 🙏