For me, to make FS teeth stronger, the FS need to chew or bite on its prey hard to kill fast...
Normal food like bigger fruit flies, medium size house or garden flies or flying ligh bulb insects good for basic teeth bitting exercise.
The medium size insect /flies will struggle hard and makes FS to use more bitting strength to kill them fast.
I normally feed my fs daily to build its body size and weight. After i feel the fs it strong enough, i'll reduce the feeding to 2-3 days once... with other
weaker species of spider or medium insect/flies as its food. When FS is hungry, and its food is bigger or feel its a threat, FS will immediately attack to kill it fast with strong bite. My primary school FS friend prefer feed his King FS with other weaker FS... according to him this way will train the fs bite to kill its opponent fast in FS fight and also makes the FS familiar to bite the weak spot of other FS. Basically i agree with him but i use different species of spider or medium size flies instead, it works well also.
How to have strong pushing power.
Strong legs and arms will give more advantage to give a powerful thrust push...
I train my fs jump many times as far as possible from my finger to its case or anywhere i feel suitable.. this will makes its rear and front leg stronger..
especially when leap and land time..
How about stronger arms?
Let the FS spar with other FS to practice its arm pushing and legs is quite common fs kakis will do.
For me, i also do something extra when have time. eg.. like..
Tap on the my arm slowly and let FS drop down on its web and let it climb up back many times..
FS will climb using its arms and legs....Dont tap to hard till the FS fall down w/o its safety web.. maybe might injured from the fall.
I also use thin string to replace its web for climbing exercise.
How to keep FS healthy and strong?
Let the FS have good rest after fierce fight.
Avoid spar/fight very sick or weak chopster.... might make FS fall sick and weak easily if its immune system cant neutralize it.
Fight with evenly strong or healthy fierce fs or healthy chopster can improve FS fight skill and increase its fighting skill.
FS is teritory dominate type.. more like home ground advantage. Strong FS normally win if fight in their own leaf nest... its opponent normally will get bitten teeth, arm, legs till broke and some get eaten. Get a good dry leaves for FS to make its nest dont change it often.. once the FS treat it as its permanent home.. whenever its comes out and see other males fs, it will fight fiercely.
There are many other tips to improve FS.. its also important as FS kakis, they must know how to identify to potential good fighter, train and take care of the FS well.

Huaaa...that's alots of useful tips given by bro viper! Thanks so much bro,u're pro indeed!
I think can try to apply some of tips aboved to my newly caught in genting..especially my
. Both of them come with good sized but no fighting will & sometime even lost to M sized spar..sian. previously i just 'train' my newly moult sub-adult with non-stop sparring with small male i caught,gotta bring them out for every hunting trip.
errr..normally i don't train my Fs,i just rely on certain "good spot" that proven mostly i caught fr there can fight well,just imagine their opponents there also an fierce type,so I guess they shud have been "well trained" in the wild...
Once I had cfm it ardy an fierce fighter then i hardly put them to fight,to reduce their injury rate due to fierce sparring. e.g my earlier batch of FSes,i almost fought them in every two days just wanted to 'show them off' in YouTube..later i found over fought them might shorten their life span & turned weaker/injured fr those silly fights. That's y nowadays i seldom post the fighting video btwn my own fighter,just wanna try to keep them fresh=healthier=stronger..& it's works on my current team!
Bro jason diff case, he no choice have to spar with his own fighter bcos no kaki ma..