[Satchmo]

They may as well buy another latest model LX-200 as they are only USD $13,500 new. The driven ALT AZ configuration is as close to ideal as can get in that setting when the public are concerned. With the low balance point ,the eyepiece doesn't change height much and the eyepiece orientation is always constant, compared to use on a fork or german EQ which would require a lot of constant star diagonal rotation for convenient viewing on different objects.

Sell the old tube and mount will offset the cost, and this time buy a few of the critical circuit boards boards now, so as to increase the longevity /service length of the instrument. In 10 years time they might require narrow band filters with an image intensifier eyepiece and the raw aperture will be irrelevant.

I can't think of any more cost effective solution- the 16" is supposed to represent state of the art technology in contrast to the old refractor, putting in a second refractor would not be true to this aim.