Keeping up the proper humidity range (70-95%) for a chondro seems to be a problem for a lot of owners. Getting or building the right type of enclosure will help a lot, but it will not take the place of regular checking and misting as needed.
As far as size goes: most chondros will not get longer than 150cm (less than 5ft).
I'm not sure what to suggest. I also keep a ball python and Brazilian Rainbow boas. The BP is the most enjoyable as far as handling goes and he's a sweety. (But I could ring his neck when he gets fussy about eating.)
The BRBs tolerate gentle quiet handling in the evenings, but if there is too much activity around they will get nervous and bite -- every time! They will often bite if taken out in the daytime too. They also require fairly high humidity (60-80%), so maybe not your best choice either. My female is just over 7ft long but most don't get over 6ft.
I'm not sure about the other types of boids. I think it would be best if you both looked through some websites or books and found a few types that you liked and then did the research to see which ones best fit your lifestyle, wishes and budget.
Don't forget that all the "extras": enclosure, heating, lighting, etc can easily cost double what you might pay for the snake itself. Especially if you get a baby and have to get a larger enclosure later for it to "grow into".
Good luck in your search!
