The night lighting regs were pointed out to me by the DAR in our EAA chapter... He pointed out to me that the operating limitations for my E-LSA RANS S-6ES (pretty standard for any experimental) reads "After completion of flight testing, unless appropriately equipped for night and/or instrument flight in accordance § 91.205, this aircraft is to be operatted under VFR day only." He went on to state that experimental of not, § 91.205 (c) states (and note the bolded portion):
(c) Visual flight rules (night). For VFR flight at night, the following instruments and equipment are required:
(1) Instruments and equipment specified in paragraph (b) of this section.
(2) Approved position lights.
(3) An approved aviation red or aviation white anticollision light system on all U.S.-registered civil aircraft. Anticollision light systems initially installed after August 11, 1971, on aircraft for which a type certificate was issued or applied for before August 11, 1971, must at least meet the anticollision light standards of part 23, 25, 27, or 29 of this chapter, as applicable, that were in effect on August 10, 1971, except that the color may be either aviation red or aviation white. In the event of failure of any light of the anticollision light system, operations with the aircraft may be continued to a stop where repairs or replacement can be made.
(4) If the aircraft is operated for hire, one electric landing light.
(5) An adequate source of electrical energy for all installed electrical and radio equipment.
(6) One spare set of fuses, or three spare fuses of each kind required, that are accessible to the pilot in flight.
He then asked me "How would you convice an FAA or NTSB hearing board that your non-TSO position and anticollision lights were 'Approved position lights'?" His answer was that if you use TSO'ed lights, you definitely meet the regs. If you use non-TSO'ed lights, the burden of proof is on you. That said – and completely 'off the record' (as in "not in my capacity as a DAR") – he suggested that IF the manufacturer were willing to provide you a letter stating that their lighting system complies with the requirements of the TSO, that would "probably" be sufficient proof of due diligence on your part. Otherwise, you would need to do the testing yourself, and be able to document all of the brightness, angularity, color fidelity, etc. through the use of certified test equipment. (Way too much trouble...)
So, until I get clarification from the vendor of my combination position light / strobe system, I'm restricting myself to day VFR. (I hold Commercial ASEL ratings, so legal at night IF properly equipped.)