Welcome MikeC82! I'm probably your closest neighbour, just outside of Oxford Mills. Lots of good questions but most are pretty tough to answer. Some of the seasoned pros here like BruceL and ennismaple will probably chip in soon :-)

FWIW I would guess that plain ol drainage is the reason your slope trees aren't running yet. Also what species of maple and how big are your trees...are they huge mature sugar maples or much smaller trees? Lots of factors to take into account. You may even have a slightly different microclimate from me even thopugh you're only 20 min drive away.