I wouldn't overthink it a ton. Having at least your complex endorsement prior to jumping into the twin wouldn't be a bad idea though. I'm not sure what places will require for that, maybe 2-5hrs? After that, do it as cheaply as you can possibly do it. Also, why are you doing your multi prior to getting your commercial? I honestly think the cheapest way to go is get your COM-SEL, then do the COM/INST-MEL afterwards.