Swimmin both will work just fine in your application and and your likely densitys altitudes.
Forgive me and my ignorance of your part of the country but I am assuming relatively low elevations.

Nitro aside from competition purposes is very useful in helping out folks who have to fly at high elevation or more correctly high density altitudes (true altitude corrected for pressure and temperature). Performance of all aircraft is directly affected by density altitude.

In this region of the country folks will tend to use 10% nitro up to around 3000, 3500 feet you will find the most common use is 15%. Then perhaps above 5000 you will start to see a lot of 25% in use.

This is speaking of two strokes .25 to 90 sized.

I have frequented a club and flying site that is close to 7000 and when a low lander shows up with his 10% and thinks its OK, everyone gathers for the takeoff show.

John