i currently use a 4 on Vandoren V-12s, should i use the same size on 56 rue lepics or move up to 4.5

I've bought a few weeks ago two Rue Lepic, a 3,5 and a 3,5+, and I must say I was disappointed with both of them. They were very freeblowing and responsive, too much I would say, the sound came out too bright without any heart. Maybe I just was unlucky with these particular 2 reeds. I'll give them a second chance soon. I usually play with Vandoren's 3 and 3,5 traditional and occasionaly with 3,5 V12's.

According to Vandoren, if you look at their reed comparison chart, the 56 reeds are a tad thinner than V12s. I find that the 56 reeds are responsive and freeblowing in a good way. If I were you, I would try a 4 and a 4.5. That way, you can see what feels best for you.