All that is really necessary is to install the standard T" or "Y" configuration, use 4 mile TF legs instead of 5, then transition to 4nm radius RF turns once the pattern is established.
TF legs that short with a large course change are not permitted by Order 8260.54A. 8260.54A is more conservative in most respects than previous RNAV criteria directives.
RF legs are permitted but they must terminate not less than 2 miles prior to the FAA. But, the FAA has yet to approve avionics (other than for RNP AR) for RF legs.