It's not hard. You can do experiments in your basement.
Ohhh dear, indeed !First, note that personal theories are not allowed here at PF. So don't expect your post to stay unlocked for very long.
Something around the mass of the sun or biggerThis is not a reply it is another question what density and quantity of matter would I require to bend a red laser beam by15 degrees?
You really should learn some real physics
Yes, it's hard to "produce" gravity in the sense that it's a relatively weak force so it takes a lot of mass to produce even a small gravitational force - we have the entire mass of the earth producing a gravitational field, and a tiny little refrigerator magnet can outpull that field. Nonetheless.....