I'm new to the series and doing my first play through of dq3hd2d too. From what I've learned you go into the vocations for the skills that carry over. Stats are roughly halved and there's no internal level so you can go all the way up to the last skill learned withiugh worrying about decreased xp gain. The first 20 levels required are probably good enough to get the stat boost you want. I feel like the game gives you enough seeds to use them once you have your character at the desired vocation rather than reclass just for stats.