The following table lists the first "clear" orbit number for
  the 10/100 (respectively) diameter jump zones. Orbits interior
to these will have to make some accounting for travel to the star's
"clear" zone (sometimes trivial, somettimes NOT)
 
      Ia       Ib     II     III    IV      V
B0    6/10     5/9    5/9    4/8    4/8    3/7
B5    7/10     6/9    5/8    3/7    2/6    2/6
 
A0    8/11     6/10   5/8    2/7    2/6    1/6
A5    8/11     6/10   4/8    2/6    1/5    0/4
 
F0    8/12     7/10   4/8    2/6    1/5    0/4
F5    8/12     7/10   5/8    2/6    1/5    0/4
 
G0    9/12     7/11   5/9    2/7    1/5    0/3
G5    10/13    8/11   6/9    3/7    1/5    0/3
 
K0    10/13    9/12   6/10   4/8    1/6    0/3
K5    11/14    9/13   8/11   6/10   XXX    0/2
 
M0    11/15    11/14  9/12   7/10   xxx    0/2
M5    12/16    12/15  10/14  9/12   xxx    0/1
M9    13/19    12/16  11/14  9/13   xxx    0/0
 
I finally remembered what my fix for this was:
    density * 10 or 100 = actual diameters of jump thresholds
 
For low-density bodies like GG's and stars, the "100-diameter"
mark is now at 20-40 diameters, which in most cases makes the
problem go away.
 
  If you want to keep the long times for gas giants, one could
wave one's pseudo-physics wand and say it has something to do
with stellar-scale fusion reactions....