+2 on the HW77. I have owned one for 15 years in .17 caliber and it does the job. I think the .20 would be awesome for your use. It is heavy but the suggestion of adding a sling will take care of that. Be careful of scope length so you don't cover the loading port. I didn't and cuss every time I fiddle a pellet into the chamber.
My scope cover the port, no problems loading.
I load by feel, you should be able too if you had the gun that long.
