I agree with Dave H. Once you've done a successful maiden (congrats!), flight testing is the way to decide the balance point. The down trim is not an indication something is amiss.

By 1917 many aircraft had adjustable stabs, and after the war it became the norm. But most of our models have fixed stabs, so the elevator trim must suffice. Trying to fit the rest of the trim to a stab that cannot be adjusted is going about things backwards.

Jim