I'm new to actually multiboxing Eve. I've had multiple acccounts for a long time. My highest SP char is close to 6 million now.

What do you guys think is the best use of multiple accounts?

So far my main is combat/astrometrics and headed towards cloaking ships and more wormhole activities.
1st alt is mostly industry and refining but I recently decided to get him into a ship so he could do combat missions with me
2nd alt is strictly combat at the moment.

I guess the issue might be, for all my combat skills, I'm flying three different races of ships -- all which have different combat dynamics. Is it silly do do minmatar / caldari / amarr together or will that provide me an advantage because of the diversity?