I have the 'freestyle' one & it does come up a bit generous - but extremely well fitting, very pleased!
I understand the 'normal' ones (which are also available new) are slightly smaller fitting. My friend has one of these & personally I don't think it fits as well as my 'freestyle' one.
So, I guess it depends which type you were thinking of?
I bought a new Landa in November and the chest is massive! I thought my boy was quite big round the shoulders but apparently not. The rain even got in to his chest
I have a Weatherbeeta Landa and it fits my 6'3" mare perfectly. I have a similar rug from Premiere Equine and it's too big (in fact I haven't used it).
So my advice is - get your horses actual size in Weatherbeeta.
I've got a Landa for my CB Cross and one for my OAP Pony, both are generous fits, so don't go up a size. Pony's is stlightly big in the chest, but my CB is a big, wide lad, and his is perfect.
I have had problems with the Landa Lightweights, with the lining causing them to slip back really badly, and in a wierd way with the outside slipping more than the in. I had to put an extra tie above the 2 on the front in to keep the front of the rug from slipping right back.