Best Practice setups for multiple LE's within Ledger through GL, AP and AR

We are on R12.1.3, do not use encumbrance accounting.  3 LE's are setup for US but only 1 LE resides within a Primary ledger.  There is one Primary, no secondary ledgers.  One currency, one calendar.  We use SLA.

Finance now wants to use a second LE within that Primary Ledger across GL, AP, AR, FA, PO.  Currently, any financial transactions were made in OU1, LE1 and JE's were made at month-end, transferring payments into LE2.  There are Security Rules defined for company segment and assigned to all responsibilities, only allowing that responsibility (AP, AR, FA, PO) to use one company segment.

setup_step_code in GL_LEDGER_CONFIG_DETAILS for LE2 are 'NONE'.  LE1 has SLAM_SETUP, INTRA_BAL, INTER_ASSG, BSV_ASSIGNMENTS, ALC_SETUP and ACCTG_SEQUENCE.