There should also be a "Certificate of Mailing" at the end of each of the pleadings/forms you completed and filed with the court. Make sure that you accurately list the address of your spouse's attorney and any other parties to the case. There should also be a place for the date, how it was mailed, and your signature. Be sure to complete that. That should generally works as the proof of mailing. I also agree that you can always file a separate proof of mailing document with the court, but sometimes unnecessary if there is a spot on the pleading itself for the same information.See question
Calculation of income is always an area of contention. Regarding life insurance, it can be complicated and I don't necessarily agree 100% with the other answer. Look at, C.R.S. 14-10-115(5)(a)(I) which lists what is to be included in gross income for child support purposes. Also look at section 115(a)(II) for what is NOT included. Gross income includes interest, monitory gifts, and trust income among may other items.
There is case law out of the colorado supreme court (In re A.M.D) which says that if if the court finds that an inheritance (as a gift) is monetary, the next question is whether the principal is used as a source of income either to meet existing living expenses or to increase the recipient's standard of living. If so, the expended principal should be included in that year's gross income. If the monetary inheritance is saved or invested, such reserved principal is not included in gross income (that's an asset, like the other answer noted). But, interest generated on that inheritance is likely to properly be considered income - but maybe the other side won't pick up on that - often they don't.
It's about how much work the other side and court want to do. If you have just put it in the bank, I agree with the other answer, list it as an asset and just see what the other side does. The court is going to be mainly conceded with your current full time employment income. So you should just list the income from your current main job.
In order to provide more complete and/or accurate general information more information would also be required. I encourage you to contact an attorney as these issues can be tricky and areas of contention.
Best of luck!See question