I made something similar to what is shown in the following in this link:
https://www.cloudynights.com/topic/1...125-dob-advice
It works well for my 12" dob. Easy to make and the cost is minimal - can use old lawnmower wheels.
Suggest it is better than a castor platform, because:
- bigger wheels can better traverse unpaved surface or grass
- wheels are not in contact with ground, except when moving. So it is much more stable.
Good luck, Peter