I typically build my water from RO using Martin’s Brunwater spreadsheet. I’m using the amber bitter profile and using Calcium chloride and gypsum to adjust. All ion levels look good accept RA. The profile suggests -11 and I’m at -50. If I add a tiny bit of sodium bicarbonate it brings it in line. Is it better to not worry about the RA if my predicted PH is 5.3 or should I add the bicarbonate?
…or are both in the ball park? 
Ignore it. Look at your calcium, chloride and sulphate levels first. I would use the bicarbonate addition to get back to 5.4 personally.
It is pointless in many cases to try to match RA or bicarbonate in water profiles.
RA is not a targeted value. It is a major influence on mash pH, but RA isn’t the target, pH is. Adjust calcium, and magnesium concentrations as desired to meet beer flavor goals and adjust bicarbonate to achieve mash pH target. Those three components are the basis of what we calculate as RA. It is because we have to vary the bicarbonate to match the requirements of the grist, that we can’t target a specific RA.
Very good. What you detailed is how I build my water. I set my calcium sulfate and chloride levels according to what I’m brewing then check the resultant PH and adjust up or down accordingly. Thanks for the info.
If you haven’t seen this… give it a read. Really great detailed overview of water chemistry without requiring a chem degree. https://sites.google.com/site/brunwater/water-knowledge