Fly whatever multi to get the 500 hours of PIC multi time that most insurance companies want for corporate flying. Time in type requirements from the insurance companies take care of the "OMFG it's not the perfect multi OEI" time requirements.

Not all of us can afford to start out in a Cessna 421/414/500/etc. If at 101 hours multi time with 98 of them 337 time the fellow gets a job at a regional, great, that's now multi SIC time, not multi PIC time. Upgrade in a few years to get the multi PIC time.

Interviewers really don't give a rip. AMF didn't as long as one can pass the sim ride. Regionals don't if you meet the total multi time requirements (i.e. ink wet CMEL rating). By the time one is ready for the majors or corporate (from direct personal communication with the directors of pilot hiring at Delta, AA, United, and FedEX), there will be other multi time in jets or heavy piston twins that will relegate the centerline-thrust twin time to a interesting story to discuss while on autopilot in the flight levels.

Tell your friend to stop worrying about if the time is golden. It's probably not for his ultimate goal, but it'll get him to the places that can get him the golden time.