before you take my advice, realize that i'm
not an expert (yet...
)
it would apearr that there isn't enough space between the gears that are being shifted. i would say you need at least double the face width of the stationary
gears, otherwise you would end up engaging two different gearsets in mid-shift.
then again, i didn't see anything saying that this drawing was to scale, so this might be a non issue.