Ulundi, if you have any doubts about a medal's naming take it to an expert for verification. If your medal was acquired from a reputable dealer, you need not worry as they will have done all the checking so that you don't have to.
You will not verify a medal's authenticity by the size of the letters on the rim. I have 3 AZW medals to the 24th and the naming on all 3 of them is different in some way, as is the detail on the actual medal, scroll, clasp and everything else. (Not hugely so, but minor variations in how sharply the details are struck up). This is due to the position down the alphabet or order that the recipient's medal or naming etc was minted. For many medals, Indian campaigns in particular (Not sure about the AZW) there were several sets of dyes at several different mints - all will show variation in detail to the design of the medal and naming. Other regiments commisioned their own naming. For example, AZW medals to the 24th, 17th Lrs and KDG will show hugely different styles of naming on the rim.
The replica medal on ebay recently did in fact have disturbingly good naming. I am no expert, but purely by looking at the photo, I could have been convinced that naming was of a an authentic AZW medal to the 24th; but it was not.
The only way to know for sure is to handle the medal yourself if you are confident of your expertise, but if you are not, take it to an expert at your local auction house or dealer.