I worked at USPS for 40 yrs, wife 36. We both contributed the max to the Thrift when it became available. Options were smaller then. My advice would be to put 30% in the G fund, interest rates are rising, and you can never lose, except for inflation, in this fund. The rest be as aggressive as your tolerance for risk allows you. Bear in mind the average return for the S & P 500(C fund) for the last 50 years is 10.33%.
As you get closer to retirement move more to the G fund to ensure no losses.
Good luck going forward, USPS is now a difficult place to work. Keep your head down and push forward. I have been retired for 14 years now, wife 6 years, and have enjoyed every minute. We have a small cow-calf operation and a custom baling business. Our place is fairly small but it is paid for. We lease about 55 acres of hay ground, in addition to what we have. Sell the production from the lease ground as our hay field provides all we can use. We are not "rich" but comfortable and can do whatever we want to.