Why not just lower the dose? The methyl form can be very strong, but you can cut up a sublingual tablet. The Methyl form is far less expensive than Hydroxy form, and stronger, so I don't see why use the Hydroxy form.
Anyway, as far as dosing MB12, in my own case I just found the dose that was on the edge, a dose that gave me some mild startup/detox symptoms but not too much. Then I have worked up from there. Pacing in the B12 protocol seems to be very important, a graded approach.