That's an old school tinkering practice to increase the performance in a setup where a single pattern cam is used. In terms of what would be better for your setup, only testing will provide you with the data... some work better with 1.6/1.7 others with a 1.7/1.6 split setup. Is it better and more cost effective to go with the correct camshaft events nowadays?.... obviously.
Well I have seen flow numbers on heads similar and it seems like they are weak on the exhaust side. They are already port and polished and I got it tuned and my numbers were low I thought. 256hp and 285tq but I also need a catback exhaust.