I'd say you need at least one Bull to make it decent.
If you have 3.5k gems, you already have one. I'm saying this because I usually get any UR from big box with those 3.5
I've tested a lot !
"1.5K -3.5k is usually what you need to get an UR from big box" !!?
You have a great sense of humour.
If you wanted a specific UR from a box, it may be at the very end of the box and at that case, it will be 9.5K - 10K.