Standover should be about an inch, give or take, between the top tube and your crotch in spandex. A tad too large is probably better than too small.

Top tube length is nearly as important as standover, maybe more so. Generally, ppl who tour prefer a more upright position than the racing dudes. This tends to translate into shorter top tubes. But, as you're dealing with a specific bike, probably not much play available to you in top tube length vs standover. The most important measurement is the distance from where your sit bones hit the saddle and where your hands hit the bar. That is highly adjustable.

Some folks are just not built right for off-the shelf bicycles, but there are lots of options to make them fit. And it sometimes takes a lot of riding to tune one in exactly. So, don't fret too much about getting the perfect top tube length, as that is unlikely to happen. Just get as close as possible(too long is better)and modify it later. Stem length, angle, and saddle position are the biggies. A local bike shop can help you make it a custom ride.