Cooling issues beyond belief!!

So, I already asked this before but Im going
to get at it again.
I had my car pressure tested last week, and
the mechanics (very good, very honest!) that
tested it said that the water pump was bad,
and that water was pouring out, so i should
change the water pump and timing belt. He
said the head gasket was good.
Ok. I did that, but went through our family
mechanic, whom my husbands family trusts,
which is enough for me. He seems to be
doing the right thing.
Then the thermostat housing was leaking, so
he changed that out. Then the radiator cap
leaked. I had just replaced the radiator cap,
but it was leaking, so he replaced that with
one of those flip top radiator caps. So, was
losing coolant for a variety of reasons. Now,
you can touch the water drip and its cold, so
its just the compressor draining.
However, my coolant was low, basically every
time I took it back for this that and the other
thing. The coolant reserve tank was
overfilled, until today, when i asked him to
siphon some of it out. I dont think he took
enough out, because it still was too high in
the reserve tank. Not spitting any out, but
after I drove the car around for a while, I idled
it in the carport, and kept checking for any
drips.. seemed like it was nothing hot to the
touch, so probably just condensor water.
Yet.. the darn thing was just barely over the
middle line again, just sloooowly creeping,  
Super slowly. I didnt let it keep running after
that, and am now sitting inside, with my
garden hose ready, to siphon out the excess.  
So this is obviously not an overheating
situation, but running a little hot, I suspect.
Earlier today, it did the same thing, but that
was prior to having the overfilled coolant
reservoir tank siphoned off a little, but not
enough.
The mechanic is saying it could be the head
gasket.
I do not have any water in the oil.
I would think that if its the head gasket, it is
only letting air in. Its the reservoir tank that is
too full that is not letting the coolant
circulate, it seems. Apparently the owners
manual says not to add coolant to the
radiator itself, and just add (WHILE the car is
WARM) coolant to the plastic tank, to ensure
it is between the two lines.

Also I imagine it could be a clogged radiator,
but the mechanic doesnt think so.

I want to siphon out a little more of the
coolant to be sure its right.
What do you think i should do?