There are a LOT more variables than just the caliber that will effect your accuracy.
Green Mountain is a barrel company so they must produce accurate barrels, and you now have a GM barrel in each caliber, which means you have solved any problem with a TC barrel.
IF you use a powder load that is identical in both, in theory the .530 round ball will be going slower because it has more mass and more surface area to cause air friction, THUS it will have more drop, because the flight time from muzzle to target will be longer and gravity will have more time to pull down upon the bullet as it flies.
But you can mitigate this drop by using more powder in the .54 to get an identical muzzle velocity..., which will still mean a slightly quicker deceleration by the .530 due to the larger diameter ball, so further mitigation by sending the .530 ball faster than the .490, and you could in theory have identical, highly accurate results from both barrels
I doubt that a deer will be any more dead if you shoot it with a 224 grain soft lead .530 ball than with a 175 grain soft, lead .490.
You may also find that when using rather light loads, you like the .490 ball for targets, as it will be faster than the .530 and a "light load", and drop less, and perceived recoil will be less too.
You will be able to hunt as long as you don't run out of both .490 and .530 round ball at the same time that the stores are all out of stock, and you also have a larger caliber IF you think your .490 is too light for Elk and you get a chance for one of those.
LD