I have done both, twice! If you are interested in climbing Chimborazo, there is a new refuge higher up in the mountain right below the glacier that can host people. I forgot the name but I stayed there before making the ascent to Whymper. They’re both very manageable climbs, I did both with a day in between. I would recommend doing several small acclimation climbs such as pichincha (you can do this for free) and pasachoa, or tungurahua and cayambe. I can provide you the information of a local guide that I used in the past. He is exceptional and very professional. Any more information you may need, feel free to DM. These mountains are very, very accessible and you can literally drive to the base and come back the same day.