Sorry, I hate to do this to you, but I only had 3 hours of sleep last night and am really tired right now, but I will be more than happy to help you tomorrow please!!
Yes, catch either:
1-2 random encounter shiny
3-5 chained shinies
Then, follow the instructions in this video for the random shiny or two.
For chained shinies, there is an applet on the RNG Reporter. I could help with that once you chain.
Yeah, if the captured Heatran's nature, gender, and IVs matched up with the one on the RNG Reporter (which says !!! Shiny, correct?), then your SID is wrong. Ask RNC to check it again. D: