My current take on this is in phases:
Phase 1
Easy check box or tag to turn off all splitting and recombine. Default to current settings.
Phase 2
Sliders or entry boxes for splitting and recombine intensity. For splitting this is simple, a number between 30 and 365 (or infinity) defaulting to 90. For recombine it gets trickier, because ideally we would be aiming it off of mint probability within a given time frame. However, I think it would make sense to add an extra timeframe to the mint probability tab of 1-year, then allow an adjustment of the maximum % chance to mint within a year at which it will trigger a recombine. Default this to 50%. Keep the easy access ‘turn off all split and recombine’ from phase 1. Note that a split of 30 and a recombine of 0% achieves the same result, so when that option is checked it sets those values and greys out the sliders.
Phase 3
Implement recombine aimed at mint pools (post cold minting) that allows small users to benefit from larger user mint chances. This must be done cautiously from network behavior standpoint, but could be extremely beneficial. Possible implementations include allowing transactions in the coinstake from various addresses and properly parsing how to output the reward in a known way (‘fair’ is less important than standardized). Some of this might be soft client behavior, some might be hard network limitations to prevent abuse of the recombine. However, we should not be preventing users from combining their coins and/or giving up information about their ownership over mint keys if that is their choice (again, this is especially relevant for mint pools). Clearly, this phase needs to be discussed more, but it is post-cold minting anyway.
I’m still uncertain how to put this into an rfc because i’m more confident about the first two phases than the third. I have always considered breaking this rfc into more than 1, but I always had an inkling that split and recombine should be treated antisymmetrically, rather than independently, and I think this 3-phase process explains that in a reasonable way.