figured bass problems

[Seng Liang]

Hi, I have a problem with figured bass in Lilypond version 2.7.17 for Windows 
(98). Here is the file: 

\version "2.7.12"

\relative {
<<
\context Voice {
\clef bass
f,8 f f f f f f f f f f f f f f f g g g g c, c c c f f f f a a a a g g g g c, c 
d e 
f f f f a, a a a bes bes bes bes bes bes b b c4 r4 e f c r4 e f c c' c, r4 
f r4 r2 bes,4 r4 r2 c4 r4 r2 c4 r4 r2 f8 f d' d c c bes bes 
a a d d c c bes bes a a d, d bes bes c c f f f4 r8 f f4 r8 f f4 r8 f f4 f f f 
r4}

 \context FiguredBass \figuremode {  \set useBassFigureExtenders = ##t 
r1 <6 4>2.. <6 4>8 <6\!>2 <7>4.  <7>8 r2 <6>4. <6>8 r2 r4 <6>8 <6\! 5> r2 <6> <6
\! 5>1 r2 <6 5>4 } >> } 

2 problems came up.
1. I wish to put two extender lines lined up vertically from the figure <6 4> 
in bar 2. But what happens in the output file is there is only one extender 
line and it extends at a point between the figures 6 and 4. Is this a bug and 
is it related to the operating system that I am using (Win98)? I know for a 
fact that the above method works ( <6 4>2.. <6 4>8 ) because when I only typed 
that bar (2nd bar), the 2 extender lines did appear.
2. How do I shorten the distance between the figured bass and the bass notes 
above it? Is it possible to change the font and/or size of the figured bass 
numbers as well? 
Thank you.
Yours sincerely,
Seng Liang.