Chiming in here, since I’d consider myself well into the ‘paid beyond my sustenance needs’ bracket.
In principle I support a policy that prioritizes the needs of more contributors. Not so much because of a political stance on the meritocratic - socialist spectrum, but because of the tribal wisdom that open-source projects that invest in their broader community typically do better. I think a broader financial support, similarly would be good for the project.
Implementation wise, there’s so many fun ways this could be approached.
For example if you imagine a chicken-or-egg situation where someone can’t financially afford to contribute much, thus not earning the Cred needed to break that cycle. You can imagine this as a “pay it forward” grant specifically to break this cycle, temporarily paying someone extra to allow them to take the plunge and eventually becoming sustainable from normal Grain distribution. Such a grant could be a distribution strategy that eats some of the budget otherwise allocated for the balanced strategy.
Whichever plan used here comes with a problem, it intends to have Grain not be exactly proportional to Cred. Something the balanced strategy will constantly try to rectify. So I think most of these ideas are moot unless either the balanced strategy is replaced with something that’s aware of these intended offsets, or we try to change the Cred balance rather than Grain directly.
On a tangent, I think it’s helpful to be on the same page with the threshold we’re aiming for as much as the number. Because similar to Changing our Grain distribution policy, I think this is the difference between the intent and implementation details.
If I’m to conjure a totally made up scale like:
- no money involved
- small incentives
- just able to do part-time
- just able to do full-time
- full-time + essential safety buffer
- competitive with job market
- competitive + sabbatical
- personal luxury
- grand personal luxury
- enough to bootstrap another project
- tycoon fantasy
I’m interpreting the proposal as capped one notch above competitive, because it includes the sabbatical. Or you could argue that’s competitive, accounting for added risk and not having traditional benefits.
Finally I’d like to argue Grain distributions aren’t and shouldn’t be like salaries. Closer but not fully comparable to self-employment either.
A more cynical take on a salary is, what shows up in your account at the end of the month because you’ve entered a hierarchical contract. The amount depends primarily on your negotiation strength (how “replaceable” you are/aren’t) and worker protection laws like minimum wages. Self-employed have a reduced hierarchy contract, but the amount is still based primarily on negotiation strength. The end result is a tug-o-war between organization profit and workers “getting what they’re owed”. (All generalization of course.)
In SC there’s even less hierarchy, a single direction promise (the Cred and Grain policies), and the amount primarily depends on your Cred. Already those are very different terms, adding onto that “plus something extra to kickstart your way to sustainability” is radical 
Either way, I think that makes this an entirely different beast than a salary. At best we could take hints from it of where people’s needs and expectations are.