Suppose an amateur astronomer finds himself watching Solar Eclipse. He can see the stars around totality. Is Sun's GR effect strong enough for the amateur astronomer to be able to tell that a particular star is appearing a few arc-degrees (or arcminutes, or arcseconds) away from where it should?
If not, what is the minimum requirement to be able to witness GR for yourself during a Solar Eclipse?
The deflection you are looking for is $\sim 1.7$ arc seconds, which should be within the seeing limits at a good site. It should also be within the resolution limits of a telescope with $\ge200$mm diameter primary.
Having said that you will not be able to see it with the naked eye, you will need to be able to photography the star field during the eclipse and again when it is visible at night and then do some arduous plate measuring and data reduction to detect the shifts of stars in the field.
So amateur equipment is up to detecting the bending of light around the Sun in a total eclipse, but if by witness you mean see the stars move with the naked eye the answer is almost certainly no.
Yes. The Tele Vue NP101is telescope, Finger Lakes Instrumentation Microline ML8051 camera and Software Bisque MyT Paramount with matching tripod is "all" of the 2017 off-the-shelf amateur astronomy equipment you need to measure starlight-bending general relativity effects during a total solar eclipse ....plus a LOT of prep work and a LOT of data analysis!
Here's some articles of interest with details of how to measure GR light bending during a total eclipse:
http://www.skyandtelescope.com/wp-content/uploads/Bruns-SAS2016-paper-v7.pdf
http://w.astro.berkeley.edu/~kalas/labs/documents/kennefick_phystoday_09.pdf
