Determining fair market value of a newly minted token for which there's not yet a market

I participated in a Realio staking event for which you “stake” their utility token $RIO and get $xRIO, which is the token their using to transition to their mainnet.

Upon staking, the $RIO is burned and you receive newly minted $xRIO. I’m trying to determine the fair market value of $xRIO at the time of my transaction. Because there was no market at the time I received the coins.

These tokens were only trading via a Uniswap pool and the liquidity was low at the start. So at first I was thinking to use the USD value at the first purchase(swap) of $xRIO for $0.014. This would create a large capital gains loss in my taxes and I don’t need to offset any profits with it.

But then I thought maybe I should be more conservative and use the USD price of the first sell at $0.1541.

The price continued to rise that day until maxing out at around $0.40.

Anyone have any thoughts or advice?