$$\Gamma_{\mu|\nu\sigma} = {-1\over 2} ( -\dot{A} l_{000} - A'(l_{001} + l_{010} -l_{100}) $$$$\Gamma_{\mu|\nu\sigma} = -{1\over 2} ( -\dot{A} l_{000} - A'(l_{001} + l_{010} -l_{100}) $$
$$+ \dot{B} (l_{110} + l_{101} - l_{011}) + B' l_{111}$$
$$+ \dot{C}(l_{220} + l_{202} - l_{022}) + C'(l_{221} + l_{212} + l_{122}) )$$
This can all be done in your head, term by term. If you get an $l$ which is $l^0_{221}$ it can't contribute to Ricci, because the bottom first and third index don't match the top, if you get $l^0_{121}$ then it is killed by antisymmetrization, etc, etc, it's all obvious, and you can do it in your head.