The YYJ Next Level and YYF Supernova (or even a Genesis) are supposed to be good for 5A and relatively inexpensive but they are over $60. Maybe you could find a Genesis for under $60, they were recently being sold on a prominent Japanese site for less than that but they’re out now.
In general I’d rather get one high-end throw than multiple cheaper ones, unless the cheaper ones perform just as well.
I’m using Takeshi dice–they weigh about 12 grams, which I find is a good weight. It’s more than the Duncan dice. A good way to increase the weight on any die is with tungsten putty. It’s quite heavy so you can drill small holes in a die and shove the putty in or like with a Takeshi die you just wedge it in the opening and add up to several grams. I found a 16 gram counterweight was easier to control but not worth the loss in spin, so, back to 12 grams for me. I would prefer a round 12 gram counterweight though. It’s a shame Duncan has a patent on them or there’s probably be all kinds of counterweights available. A 3/4" diameter ball with a mass around 12-13 gram would be perfect. If I knew how I would make one out of a heavy metal sphere (like lead or something) coated with rubber. Oh well…
What exactly do you mean by saying a bearing has a “maxed out gap”? I heard the Leo Sniper Mk II had very powerful spin but have never used one.