Baking soda is used to alkalinize your GI because amphetamines are much better absorbed in an alkaline environment- this is effective when taken orally. Anything that acidifies your urine will keep amphetamines in your blood for longer and can help prolong their effect.
L-Tyrosine im sceptical on its effects, some studies suggest it is useless and doesnt make it pass the blood brain barrier whereas on the other hand some people report it helps them. Some also report that it did nothing for them. I have seen many amp users say that L-Tyrosine is good for when you feel yourself starting to comedown as it helps ease the crash. Some also say it increases the peripheral effects.
Theres really no way to potentiate amphetamines besides the way of increasing oral absorbtion and slowly excreition, and I wouldn't want to really help you do that in the first place.
Take the L-Tyrsoine on the comedown and eat. Well try to eat it helps %)