My question involves a child custody case from the State of: Colorado

Ok, maybe not spicy but maybe so. You be the judge.

#1
I have an upcoming contempt hearing for contempt for my ex not paying child support (and other stuff but that's detracting from this). In a past contempt hearing for him not paying Court Ordered money owed for things unrelated to child support, he produced money orders he paid to me that were actually paid to me as child support as I understood it at the time and he got off the hook for that contempt bc of that evidence. Now this child support hearing is approaching and he is using those same money orders to show that he paid support. As I am pro-se (and he is represented), what is the best way to handle this? I have the full transcripts as exhibits where he provided testimony that these money orders were not child support as well as his previous exhibits where he claimed them as non-support payments to fulfill the obligations of that contempt hearing. I know there is a loop-hole where you don't need to disclose exhibits in advance if you are trying to catch someone in a lie but as I am pro-se and he is represented I didn't want to mess with that so he already knows that his previous testimony and exhibits are part of my exhibits. That being said, I think he still might try to pull off that those money orders were support.

My understanding is that we both give an opening statement, then I give my testimony/call witnesses and then he does the same. If I have to blow my legal load (sorry for the technical phraseology) in my testimony before he gets on the stand, he won't perjure himself because I will have already explained the lies that his exhibits hold. How do I best navigate this?

#2
My ex submitted as an exhibit a complete record of the child support payments he has made. Although there are many payments included in his spreadsheet that absolutely never happened and as such there is no evidence to substantiate them, there are many months where only partial payment or no payment at all was recorded. Can I take his own data and aggregate it into a spreadsheet even though it is after the date for us to exchange exhibits? It is really only the arithmetic of his own exhibit but it would be great to be able to say that "Respondent claims to be current but using respondent's own number's they are $_____ behind, $______ including interest. I am not introducing new evidence, just extrapolating from what's been provided.

Hypothetical numbers: He owed $10,000 principal total using my numbers. He claims he owes zero. When putting his actual numbers submitted as an exhibit he owes $4,000 principal. Can I show the court a document I made showing the arithmetic of my ex didn't equal a zero balance but $4,000 owed even though the time of exhibits has passed? Does that exhibit need to be accepted before I can use it to refute his claim of being totally current?