confused on cost basis

I've used FIFO the past several years. Can I switch to the new beta optimized HIFO if I want to or what are the rules in the US for this? Do I have to stick to FIFO forever now?

Also my "wallet based tracking" option has been on from the beginning. am I correct to assume this whole safe harbor and universal thing doesn't apply to me? i think I've been doing it wallet based all along..

thanks