Hi folks. Was looking for a little advice please..... There has been some similar posts recently but I have some additional queries!

I've been hunting for a navy blue blazer that I an wear with jeans casually or more formally with chinos. I really need one prior to the weekend. I'm slim built, 6ft1 with a 38inch chest / 32 inch waist. I usually wear a 38 long in a suit jacket to get the length in the sleeves - regular fits in the body a lot of the time but is too short on the sleeves. I have my eye on two at the moment but I'm undecided.....

The first is from Reiss:

Jeffery Navy Herringbone Two Button Blazer - REISS

And the second from HE by Mango:

H.E.BY MANGO - Sale - Herringbone wool-blend blazer

Can the Reiss blazer be worn casually with jeans or is it too formal? What is the sleeve length like with Reiss blazers? If anyone has this does it look as dark it's it does in the photo (almost black)?

Is the quality of HE by MAngo blazers good? How do they fit size wise? It says a size small should fit me going by their size guide but I'm usually a medium with most brands... The one I like has only a small left in stock and no medium so I can't order both.

Any advice (or alternatives) appreciated. Cheers