Like BenThayer said, "you should ask you water treatment consultants or resin suppliers".
In addition, you should keep a few things in mind:
1. HCl is a more efficient regenerant than sulfuric acid, resulting in higher resin capacities and lower sodium leakage.
2. Unless you are treating soft water, sulfuric acid will result in the creation of calcium sulfate. The regeneration process/sequence will need to be modified to allow for a step-wise introduction of the acid to prevent the formation of calcium sulfate precipitate in the resin bed. This will require some piping and valving changes, the extent will depend on the method used for the introduction of the acid (eductor or pump).
3. If your cation uses a separate acid distributor, it will most likely be necessary to examine the lateral hole sizing, based on the new acid flow rates, to maintain an even flow distribution.
Anyway, just some random thoughts for. your consideration.