Salaries are a business expense. If you hired a second programmer would you not expect to pay them? So why wouldn't you expect to pay yourself?
I've thought a lot about what the dollar value is of my time and I haven't come up with any way of reaching a number that I find practical. It can't be my earnings, because that's negative. It's not 0 because I do value my time. It's not my opportunity cost from not doing consulting work because that would just tell me that I should outsource everything. I could just make up a number like $50/hr, but I don't know that it would help me make decisions that I couldn't other make.
As an example, PayScale says average software developer salary is $67k in Springfield, MA. I would recommend you put this down as an expense and a liability or equity in the business within the context of the "accounting equation"; see https://www.investopedia.com/terms/a/accounting-equation.asp
The key here is to make explicit your opportunity cost. You can then put that in context of how much you are willing to invest in this business. For example, if you wanted to give yourself a seed investment of $300,000, this could mean $50,000 cash and 3.5 years of labour.
If you counted that as a liability you could say the business has to pay you back once it reaches profitability. Or if you view it as equity you would build that cost into when you sell your business. This would also allow you to better calculate ROI.
If you account for your time this way, you can cleanly separate business and personal expenses. In terms of the "4 hour workweek" way of thinking, it also means you know when you can stop implicitly throwing money at your business and hire someone to fill the "dev" role and have the business run itself.
If you will indulge my 2c, I would also recommend you cut any projects that are not performing to your expectations. When you have multiple projects you are acting as portfolio manager. This means that you are modelling your business like a much larger corporation with different business units, which require far greater management overhead.
From reading your post, I believe the role you envision for yourself right now is that of product owner/manager. If that's the case you should limit the scope and complexity of all other responsibilities so you can do that role well.
>I could make up a salary for myself, but it would kind of be pulled out of thin air.
The exact value of your salary doesn't matter, it matters that you've factored something in so you can keep a roof over your head and feed yourself. By not factoring in your salary, you're painting yourself a rosey-er picture of your financial state than it actually is. By your current measure, your venture could be "in the black" yet you'd still be struggling to make ends meet. You need to see the picture as clear as possible.
>all my other expenses are objective and quantifiable
If you expect this of every expense, then you'll be in for a shock. Many business costs are not objective in the sense that you can rationally determine why exactly it costs X. Heck, pricing software is mainly an exercise in "what's it worth to you", rather than what it costs to actually develop it. If you need absolutely need a service and only one consultant can offer it, then chances are you'll have to pay what they ask, even if there's no objective rationale behind the costs other then that's what they charge.
My point is that the business side requires a different mindset and perspective than the technology side. You've got to improve your business skills in the same way you'd improve your tech skills. It's not easy, but at a certain point your success will depend far more on your business acumen than it will your technological prowess.
(If its a sole proprietorship, I'm not sure shat the rules are)
At least prior to the recent corporate tax rate cut, the tax you'd pay on the salary would typically be less than the sum of corporate income tax and tax on the dividend, so people would pay themselves unreasonably large salaries to save on taxes, and the IRS would object to this.
Here's an article that goes into more detail:
https://www.forbes.com/sites/anthonynitti/2016/05/13/reasona...