Need help! C10 or C20

[Shak]

I am interested in getting a 67-72 truck as a project for my son and I. I would like a C10 for its collectability. I am having a hard time finding one that fits my mechanical abilities, but there are a ton of C20's. Can the C20's be lowered just like the C10's, or are there considerations I am not aware of. I would assume drop spindles and lowering springs would be the same on each, but I am worried about suspension differences that aren't so apparent. In fact, I'm interested in any differences that aren't so apparent. You have a great web site, which has already proven very helpful towards our ultimate goal. Any help you can provide would be greatly appreciated. Thanks.