ATM 8" f3.8 -- Worthy project?

["Matt Terry" <mterry@tampabay.rr.com>]

  Hi there glass-men and women,

     A couple of quick questions:  How  many folks have made sub f/4
smallish
  mirrors?  A mirror class member wound up with about 3.8 on his 8" and got
  discouraged from figuring it.  I do not often read about such speedy
  parabaloids, though I have looked through a 41" f/3.1 at the Grand Canyon
 SP in 1998.
      I'd like to see if I can figure his mirror, but, are there testing
limitations or impossible coma problems at f/3.8? Would such a mirror prove
exponentially harder to figure than, say, the 6" f/4.25  I managed to bring
to one-eleventh wave?  That doesn't seem likely, but there must be a reason
such short focalities are not oft made, eh?

  Thanks,
 Matt