I have an excellent Lumicon GEG with extension tube for ST4 use, and a 12" LX200 adapter (I believe it works for the 10" also)
This off axis guider /reducer combo allows you to use focal lengths of f/10, f/6.5, f/5.5, and f/4 with a 35mm camera. In almost mint condition. Comes in a new padded hard case with extra screws and hardware.
Can ship to your door for $325
Thanx for looking!