I've had no issues with either of my tripods. I have a Manfrotto 290 that is lighter duty than most people would recommend but had no issues getting up to 2-3 minute long exposures with 300-400mm lenses. Others have not had as good of luck with light duty tripod so maybe my results are outside the norm.
I more recently got a much more heavy duty carbon fiber Innorel RT90C (it was $300 on amazon), 88lb rating. I mainly got it for mounting heavy lenses on gimbal head for bird photography and it excels there too. But I dislike all the twisty leg logs, I like flick-lock style better, my only complaint. Others have used the wooden surveyor style but I think they may need adapting to different mount bolt, I'm not sure on that.
I do see the iOptron 1.75" in stock at Highpoint scientific... (if its compatible with Skyguider... I think the one aximuth bolt may be removable?)
Edited by T~Stew, 25 February 2021 - 11:50 AM.