Find a large boat shop (or shops) near you and go try on vests. Riding and fishing have entirely different motions.
You might want to go when the store's not too crowded so you can "air-fish" while minimizing the possibility of being carted off for psychiatric services.
Some vests are machine washable, might be a benefit if you plan to fish in it much.
Once you find one you like, write down all info and check online pricing. This time of year you can usually find the vest you like at a substantial savings online.