Re: Need advice-1 piece shooting rests??
It sounds like you are shooting off a bench. If that's the case, you will be best served with a high quality adjustable front rest and your choice of the many rear bags offered.
The one piece rests are certainly the best option to enhance your accuracy but not needed for what you are doing.
After some "bench shooting", you can replace the front rest with a bi pod, and utilize the rear bag for some belly shooting.