since you have the skis, go ahead and take the skis up for a day. just ease into it and don't immediately go hit the doubleblack /skull+crossbones runs where falling=death.
Maybe they'll be what you want!
There's always some old guy in the lift line the straight skis in the lift line that everyone stares at for a bit.
Especially since they are the skis you are used to, you may be familiar with the straight-ski techniques to hotdog pivot instead of tipping the skis and having the shape turn the ski for you.
If you are set on renting, I'd suggest to take a look at the skis that have full rocker, as this will be more familiar to get into, while you learn the carved turn. Perhaps the Volkl rtm84 would be a match to your old school technique. It has a top size is 181cm-still short, but it is beefy. It should also be widely available in the demo rental shops, and is a season old.
It still may take you a day or two to figure things out, but having the full rocker will help ease you into trying the tipping to turn rather than pivoting. This is what worked my friend who also was a straight-ski skier.
Anyway, i'm still a noob and the experts over in the ski training area will have better advice on technique than I can provide. And if it's a good rental shop, they can give better advice based on what they have.