Trying tio get lofts to work- help needed

Hello,
I have been trying to get a solid loft to work that uses four section
sketches and about a dozen guide curves, but have been finding it
problematic. All the section sketches are closed and all the guide
curves intersect the section sketches.
The feature I am trying to loft is symmetrical so there are several
mirrored guide curve pairs.
I am finding that getting a loft to work in SW cn be quirky and is a
bit of a hit n' miss kind of process that can lead you up the garden
path.
eg. You select all your four section sketches and arrange them in the
right order. Sometimes SW shows a succesful loft preview without even
selecting any guide curves. So you now select your guide curves and as
you do, SW can jump from showing you a successful loft preview to not
showing any and giving you the "Loft operation failed to complete"
error. This can occur as you select/deselct each guide curve.
It seems like only some combinations of guide curves result in a
successful loft. Strangely, I have found that there are cases where if
I select both guide curves of a mirrored set, SW will fail to complete
the loft, whereas if I just select one, it will successfully complete
the loft, albiet not in a way I want it to.
To try and avoid this, I have even tried lofting just one half of the
feature, using one half of the sections skecthes and just one of the
guide curves from each mirrored pair. Even here I run into problems
with the same error "Loft operation failed to complete".
These light blue connector dots/strings that appear are also a bit of a
mystery. I don't understand how SW decides where to place them (by
default they always seemt to be very wrong) or how many it decides to
use, or even which blue conenctoir dot string it decides to show by
default (right clicking on teh dot can "Show All"). Sometimes these
conenctor dots can be dragged freely along a line segement but other
times they can only be shifted from discrete positions at each vertice
in a profile sketch, which is frustrating in itself, especially when
adjacent section sketches don't share the same number of vertices. I
don't understand whats runnign the show there.
What advice can you give on getting these lofts to work the way you
want them to?
Are there a set of firesafe rules for creating profiles and guide
curves to ensure a successful loft? eg. symetrical parts should always
have a vertice on the sketch coincident with the plane symmetry and a
guide curve running along it, or if you use enough guide curves, the
loft will eventually work etc
Regards
Bullman