Jason Miller explores this question in his
"Elements of Spellcrafting" (Ch. 6, "Future or Present Tense?" section) and he uses prosperity as an example as well (spoiler alert: Miller argues
against using the present tense). Miller is moderately famous for recommending dividing up big goals into subgoals or seperate stages leading up to the one Big Result. Saying "I am financially stable" when you patently aren't would be too abrupt a step for my liking and I'd be afraid my subconsciousness wouldn't buy such a bold statement because it's simply too outrageous given my present situation. It's what I don't like about affirmations as advocated by NewAge writers, all that forced chirpy optimism - I'm much too cynical for that.
However, I would be able to stretch my capacity for suspending disbelief for statements like "I am
becoming more and more financially stable", additionally incorporating the way this financial stability should come about (which is tricky with a chaos sigil where short and simple sentences are best IMO). Of course this runs counter to the philosophy of that school of thought which warns against limiting the universe or whatever in the way your magic is supposed to specifically happen but then you would run the risk of being saddled with extra work hours, for example, like you mentioned.
In short, I would focus on the
process of reaching a given goal, and this is why I have become a bit disillusioned with chaos sigils - they are fine for specific short-term results but rubbish when it comes to more general and open-ended positive developments (but that may be just me). Furthermore, I'd subdivide your end result of financial stability into seperate subgoals, for example spending behaviour, sources of income, awareness of day-to-day bank account balance and credit card statements, etc., where you can be a bit more specific instead of trustingly leaving everything in the hands of fate and a supposedly caring universe.
I remember one cartoon (in Jason Miller's book?) where the magician loudly declares "I have a million dollars!" as his statement of intent, and the spirit goes "Yeah whatever, dude" and does exactly nothing. That one gave me pause...