There is absolutely no need to get on a trainer. V-brakes are way more grabby than caliper brakes and you do 2000km a year with those, so you have nothing to worry about with road brakes. Just remember to keep your weight back and that's not something you'd learn on a trainer anyway. You'll get no sense of how the bike rides w/o a road test ride so get on a few and get a sense of it.

In general, most bikes within certain price points are the same with minor differences, so get the one you like best and then get a fitting to get the bike fitted to you.