TMUX attractions

tmux needs to be started using the -2 switch, to enable 256 colours (two-bytes?) mode. Can this be set in .tmux.conf as well?

Also, for programs running within a tmux session to understand that the terminal supports more than 8 colours, the $TERM variable should be set to one of the known terminals which support this, such as xterm-256color. But by default, tmux sets this variable to screen. Need a way to configure/override this so that I may use 8-bit colour terminal codes instead of 4-bit, for things such as my custom Midnight Commander theme, or bpytop, tide prompt, and so on.