Question about Roman Catholicism?

I am curious about some things/rules within the Roman Catholic Church. I currently attend an Episcopal Church and consider myself to be an Episcopalian. One thing I love about my parish is everyone can be as Formal or Informal as they like. I myself, am fairly formal (Kneel, Cross Myself, Bow My Head When Appropriate, etc...) or "High Church" but my mother and many others are not at all. I am wondering do Roman Catholic parishes or the "Church" in general allow their parishioners free reign on how Formal or Informal they are in Worship/Eucharist/Mass, or is it very rigid and guided by a strong set of rules? Also are Roman Catholics required to pray, or invoke in prayer, to the Saints, or is this a personal choice? Thanks