I have worn 286s, 325s and 345s.
They all leaked because the fabric wore where the toes and foot flex.
However, having flirted with Salomans, I think I am going to buy another pair of 345s. The grip is amazing (its not hype) and they are extremely comfy.You can do miles in them: the Duracell of footwear.
If you are stacking the 345s vs 325s, I would recommend the 345s. I found the 325s were a little slippy on rocks.
I try to avoid wading streams with boots on, so can't comment on their ability to drain. However, the 345s started leaking as I was walking into Knighton on the ODP and I did not enjoy dry feet for 4 days afterwards due to dew and rain.
Remember they WILL eventually leak-I expect 100 miles before they fray. Take Sealskinz.
I always buy a size bigger with Inov8.
Buy from Ultralight Outdoor Gear-they have a good returns policy, though you have to shoulder the postage.
Just a thought-have you considered the 275 Trainer?
Like you, I like a high cuff, but might try the 275 next year on the Coast to Coast-with Gaiters.
In summary, a good boot, but expect wet feet sooner or later.