Angle grinder questions

1 how much you plan to use it justifies what model and price you are willing to pay.
2 corded or battery. Corded can run longer periods of time and have more power. If you are doing small projects lenght of use is not so important.
2 go to different stores like a lowes ,harbor freight, put different units in your hands , try out the switches,as you said paddle is the best for quick control. Also variable speed sometimes you do not need 20k 5k will do the job.weight of tool you may brake using this tool for hours
4 protection wear long pants and a good fitting shirt long sleeves are best. A hat and most of all eye and ear protection. High frequency noise can effect your hearing over the long term trust me I wear hearing aides, eye protection but good fitting safety glasses with good side protection and buy 2 or 3 as they get dirty and damaged by the flying debris. Good heavy gloves.
5 when using this tool or any power tool patents is the key do not try to remove all of what you are going after on the first pass, several lighter passes are easier on you and your attachment. If it comes off in one pass great or it may take 5 or 10. Do not work one area to long keep moving and then return ,so not ot over heat the material you are removing as it will become soft and start to penetrate even deeper into the porous base material .
6 take breaks and check your progress. For me it is a fire box I want to remove all loose carbon and debris, I am not wanting to try get back to clean original surface. During your breaks feel the surface with a rag to see if you are getting material transfer if not that area should be ready for the wipe down phase.

I know way to wordy and you are not 15 years old,sorry habit.

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Link to Hengxuan Abrasive