One of the great things about an LLC is that the amount of distributions does not have to be proportionate to the financial contribution to the business, so, an LLC looks like the correct choice for you.
Beyond that, you have an unlimited number of options for determining distribution percentages. You could base it on expected hours worked (200 for your spouse, 40 for you, 40 for the CPA). You could base it on capital contributed (25% each for you and your spouse, 50% for the CPA). The most fair distribution might be one that takes the value of the spouse`s work into account (say a $50k salary), and then have the remaining profits equally distributed between you and your CPA. The bottom line is that you three have to agree on a scheme. When discussing it, be sure to work the numbers for a best case, expected case, and worst case scenario. Things that look great under a best case may not be under a worst case scenario.