IMHO, no. Get your alternator tested and repaired as necessary. If you have never seen more than 25A charging rate, either you have never discharged your batteries very much or you have other problems in your electrical system. Inadequate wiring, bad connections, just to name a couple. If your batteries are healthy and are staying charged, why do you think you need to replace the alternator? As far as a 35A alternator, I have not seen one in 30 years. And the 35A rating is for peak current, not average, not RMS current, and it is only rated at a cold alternator. A typical automotive internal regulated alternator rated at 35A will actually only put out about 24A RMS when cold and probably 30% less when hot. You have asked an apparent simple question but the answer is complex.