Just watch out for side effects. Really high methyl doses may activate stored mercury in the body.
http://www.whale.to/w/b12.html
However, this remains to be confirmed further.

Those high doses were done with medical supervision. And in the studies were IV I believe. Taking orally is very different. Most of the B12 will remain in the intestines.

High dose B12 in the past had acne as a side effect, but I believe that was with Cyano form. (the cyanide in it might be problematic for some people).

I would space out your multiple doses. This is because there is a carrier in the small intestine which has limits on how much it can latch onto. This carrier is called transcobalamin.

One can search all day about these topics online. I don't really think it is 100% safe to take such huge doses orally. This might become more of an issue over time, as well. The B12 itself is not toxic unless someone is intolerant to cobalt, which is rare.
It is the other effects that B12 may have on the tissues that haven't been studied in depth yet.

Oral B12 is not well absorbed normally, so a true toxicity is not likely from it.