Actually, the Vulcan website has two selection aids. In one you input boat length and weight. The V25 is their recommendation there for a 39 ft. boat weighing 39k pounds. The H38 has a dry weight of 30k pounds.
Then there is a table. The V25 is in the middle of the range. Going down to a V20 puts you into a recommendation for a 22k pound boat or less. Going up to a V33 puts you into recommended boat weight of 66k pounds or less. A V33 seems excessive, in spite of the standard advice to go up a size.
Further, my concerns up front were whether a V25 would fit the boat. It will. But going up to a V33 might well be pushing it too far. And the V25 selection seems to have more than enough extra heft built into the selection.
https://rocna.com/fitment-guide/
Then you get into chain. H38 comes with 200ft of 5/16 HT chain.
If I read the fitment chart correctly, go up to a V33 and 3/8 chain is recommended. And then you get into windlass, and so forth.
Taken altogether, it seems to me the V25 is plenty, and going further creates a series of issues.