[...] the recommended bend radius for these ropes is something like 3 or 4 times the rope radius [...]
That's the recommended *minimum* (3:1). Naturally, the more evenly distributed the force (the larger the radius), the stronger the structure. Incidentally, I requested a plot of D/d strength from Samson but they don't have it (nor do they have any knot testing results for their Dyneema products).
Those are some beautiful buries you guys are making, but I'm hooked on hitches.