I am quite a beginner so I do not think I am in position to give to anyone any advice. But I think I can share any useful information I came across looking for racquets and tennis equipment.
So take a look here
I found there that there is a formula to evaluate the quality of a racquet. The formula goes like this M*r^2/I. M= the racquet mass (they mean the weight of a strung racquet in kilogramms), r= is the balance meaning the distance in cm between the butt of the racquet and the balance point and I= the swingweight.
So if the mass of the racquet is 300 grams it means 0.320kgs, the balance of the racquet is 30.5cm and the swingweight is 305grams you should get the following calculation
Any figure below 1.10 means the racquet is good. Above 1.18 is bad and I guess 1.10-1.18 it is mediocre.