Not sure what a financial advisor costs, never hired one personally, but if you just ballpark scratch out your taxable income then make your quarterly pre-payments (even now despite missing April's payment) i am willing to bet the lost interest on over-payment or penalty from underpayment will be substantially less then the cost of his services for this particular issue alone. I even think there might be a provision if you end up paying 90% of your final bill from regular withholding and the total bill has grown year over year by like 110% then there is no late fee at all for underpayment (someone fact check that).
I mean if you are intending on establishing a relationship and he will be providing you with other services beyond this tax prep, then ok sure hire him. This might actually be a nice icebreaker for starting said relationship. But really, if you are just a w-2 wage earner with a non-taxed bonus and are taking standard deductions its not gonna be all that hard to figure out. You could seriously get to 85-115% accuracy with minimal effort.
I am not sure how it is for the rest of you guys, but I am pretty anal retentive with my finances. I have an excel spreadsheet that I keep all my investments, expenses, tax estimates, ect. Back when my taxes were super simple (read: 1040 EZ) I made a tab to record year over year tax bill and even now with my taxes being much more complex I can still mostly fit it into the original columns i set up back in the day (with a little fudging and hard coding numbers for stupid shit like AMT). I actually still use this tax tab to estimate my taxes as i have some chunky ass income courtesy of being bonus heavy and a few k-1 schedules that surprise me at year end with a burden. For the most part i get it pretty close on my prepayment. For example this year i ended up having a late payment penalty of $1. Those pricks actually deducted my refund for a de minimis amount like that, go figure.