Id say your best bet is a set of textiles but you could always go to a shop and try both leathers and textiles on over your clothing to see what you feel most comfy in. I personally wear textiles to work as i find the trousers easier to get over my work trousers and the jacket breathes a little bit better so i dont turn up with a soggy back! Also there are no locking facilities where i work and id rather loose my £200 each or so textiles as opposed to my £450 odd leather jacket and trousers! At the end of the day leathers or textiles is personal preference though! If youre going for leather jacket, like has been said it needs to be quite snug, if you hold your arms out and try and twist your arms, the armour should move with them. Like vicki said though, they should explain in the shop Good luck