The speedy 30 may look small to you now, but honestly it fits the world! I actually find it quite big on me now and wish I had the 25... well I don't know, it's only because small bags are 'in' at the moment so maybe that's why I feel that way. Either way, speedy 30 is the most classic!
Regarding the collinol spray, i have written about my experience with it on another thread but i've copied and pasted what I wrote:
''I have the same one (with the UV protection) and have sprayed it on my neverfull vachetta and vachetta tabs on SLG's with no problem, and they are totally waterproof- i've ran it under tap water just to see, I know I'm mad haha.
Like previous posts, give your vachetta some sunlight briefly maybe a few days or something. Then give the bottle a good shake, spray from a distance evenly in open air outdoors if possible. You'll notice the vachetta goes dark or have uneven dark spots and it freaks you out but it dries within a few seconds and disappears. I once sprayed it on my TP19 vachetta tab on the back and i had a huge blob, looked like an oil stain and I was so gutted but then after 20 minutes it totally disappeared. Doesn't stop it from patina, just protects from rain etc.''