I guess the Selmer and Buescher mpc's have bigger chamber which give you better low tones? On the other side your playing in the upper register perhaps is better with your Link?
We are all differnt. I like to play the low tones and I found them more expressive compared to the high tones. I can honk of the palm keys and some altissimos but the low tones are my thing. Over the years I have trained and developed the low tones.
Practise; longtones in differnt patterns, various volume and effects (growl, note bending, vibrato ...
A good sax; a well regulate and well sealing sax, there are differences among saxes. The "jewel in the crown" (IMO) when it comes to low tones are Martin saxes.
A good mouthpiece; I'm not able to blow the low tones so well on Dukoffs, Larsens compared to my current mouthpiece, Rovner Deep-V.
Reeds; this is very personal. I like "lots of wood". Vandoren V16, platiccovers baritone reeds, bass clarinet reeds ..... and I also like hard reeds because I use to blow/push hard/loud.
If you like to be a more allround player (jazz, big band, concert band, classic ...) and play sax in differnt genres my advices are perhaps not the best. But if you decided to do your own thing there are differnt ways to go. I replaced my last saxteacher with a teacher the taught on electic guitar.
Off topic again!?
Thomas