Try out some Epiphones or Gibsons with the 59 round back to get a better idea. The 59 round back is not as fat as the Warmoth Boat, but, I doubt you'll find a Warmoth Boat on the store rack. So, the Epiphone or Gibson neck should give you an easy to find indicator.
i've owned Nash's with medium C, fat C, and medium V. I'm personally not too clear on if the "boat" is a fat V, but it appears to be. Personally i've grown into my Fat C after never having played fat necks, and i don't think i'm going back to medium's for the most part. I'm doing more chord work then solo's, so if you're a lead player ymmv....
Nash's medium C is a bit fuller to my hand then the average USA Fender neck. 9.5 radius vs. 7.25 i believe. If you're fairly comfortable with an everyday Fender, get a medium C.
Maybe call Kali music, off of Nash's dealer page, or another dealer that does a lot of Nash business, even if you have a different dealer you are purchasing from. They should be able to give you an in-depth talk-thru of the neck feel and fit...
There is just no way we can predict for you whether you will like a specific neck profile or not.
Moreover, Boatnecks and V necks are not necessarily the same thing - many say a V has a pronounced keel or index line with can be imposed on almost any neck shape, while a Boatneck is simply a very deep or large neck with very little "shoulder" and possibly no discernible index or keel line at all.
I suppose you could blind order a Nash and then start shaving it down until it began to feel right, then stop and get used to that. Don't take off too much. I kinda shivered when you said Nash because I tend to like really big section necks like No-Casters and Allparts TMO-FATs, but the last big neck I truly could not play at all was..................................a Nash.
Yeah well I have a mexican made Tele that has the basic c neck and I hate it. It just doesn't play good. So thats why I want to get a nash guitar and I'm hesistant to either shape. I'm nervous that the C will play like my tele and that the V will be too big.