I'm not sure whether dropping a bit of string tension might make the sweet spot feel bigger. I must admit I don't find it too small on mine.
I also added a leather grip to mine to give it more static weight and make it a touch more headlight. I guess it effectively turns it into the Tour version but with a 16x19 pattern and 1 extra square inch.
Ive tried a few rackets and settled on the Bio 300. Its a really nice racket to play with. Plenty of control with more than adequate power once the leather grip is on.
Lee, how are you finding your Bio300 Tour?
"Tennis is just chess with balls."
Sometimes: Dunlop Biomimetic 300 - Sometimes: Prince Exo3 Graphite 93