Almost certainly you should make different curves for each developer. Ammonium Citrate tends to be a bit contrastier than Potassium Oxalate. Do the oxalate linearization first, then print a target with that curve, print it in the darkroom and develop with citrate. Most likely it will be a bit contrasty, but not so much that it can’t be easily linearized using the standard method (i.e it won’t need to be limited.)
If you use different papers or different ratios of Pt and Pd you may want to make a custom curve for each variation. Alternatively, you could use a single quad curve and make a custom ICC profile for each variation to be used with that quad curve. We have options!
Keith