Jeffrey, Welcome to the jewelry world! The problems you have
described are common to ring sizing. There are several issues
here...one is dry hands, another is the difference between knuckle
size vs upper finger size, the specific shape of the inside ring
shank is another.
Often you will find that the size to get a ring over the knuckle is
such that when worn above the knuckle the ring is too loose, even
with sweaty palms. One way to prevent this is to solder sizing balls
into the lower quadrants of the shank (see archives on sizing balls).
Another is to alter the shape of the inside shank similar to a
"comfort fit" style. The inside is made more rounded rather than
flat. This better allows compressed skin to enter the ring (i.e. slip
over a large knuckle easier) and yet the inside diameter can be a bit
larger than if it were flat. If the condition is really acute, there
are shanks that actually snap open on the market, see Stuller or some
other suppliers. Another factor has to do with the width of the
shank. Narrow shanks tend to allow more flopping around than wide
because there is more friction in the latter...there is more skin to
hold the ring in position.
If you can make the signet side of the ring a bit lighter by
hollowing out the back etc, that might help stop the flopping as
well. Remember that each person's fingers are constructed
differently and while it may not flop on your finger, it may on
dozens of others even of the same size (approx).
Hope this is of some help to you....cheers from Don at The Charles
Belle Studio in SOFL where simple elegance IS fine jewelry!