You obviously forgot to calculate how far your accelerators would have to be spaced out if you're accelerating that slow. At 2g and 60 days, your system would

You obviously forgot to calculate how far your accelerators would have to be spaced out if you're accelerating that slow. At 2g and 60 days, your system would have to span 263,632,527,360 km. That's more than 10 times further than Voyager 1, which is tiny space probe that has been traveling for 47 years. And that also assumes that your light to speed conversion is 100% efficient and that you can hit the 1-gram target perfectly over 263 billion km. Sorry, it doesn't work no matter how you slice it.