You have two products:
1. Cards. The paper shall be Verge or Color Plus (cheaper) 180g or similar, because the customers write in, cannot be a paper who absorbs ink or blur
2. Print Art. Well, in this item you can follow the tips of everyone of us, including mine.
cost / benefit: Hahnemuhle, German paper, 100% cotton,
Canson Gravure, French paper is the best I have ever used, but very expensive .
Good Luck from Brazil!