John Meadows is a HUGE advocate of a peri-workout beverage.
Taken right from his fourms:
" If you are cutting or goal is to lose fat, 80% of your carbs should be around the periworkout period. If you are an off season status, then 60-70%. Thirty (30) grams is relative base on ones diet. If you are consuming 200 grams of carbs daily, that would be half your normal intraworkout nutrition days (60). But if one is only consuming 100 grams of carbs daily, 30 grams maybe the normal carb amount during the periworkout period"
" I believe he advised it should be a 2:1 ration of carb (HBCD) to protein (casein hydrosalate). This I believe is more applicable to off season or if one is consuming moderate to higher carbs. If you go to low carb or keto diet, all you will have is just the protein or BCAA/EAA and no carb."
Personally I would start with at least 10g of BCAA's/EAA's and then add the carbs as needed (Say 30g to start and work your way up to 50-60-75g) and see if you notice a difference in your training.
Lets also factor a few things:
1) What does your pre-workout nutrition look like? If you are eating a meal prior how many carbs and how big is that meal?
2)What does Post-workout look like as far as calories/macro's go?
If you are covering your pre-workout nutrition adding in extra carbs is really a buffer if you have the extra calories to spare it would be optimal to put them when the body uses them most (during your workout) to enhance your performance and endurnace.
Throwing in more protein is really only elevating MPS the entire time from pre-workout, through intra-workout and even post-workout. So it does not benefit MPS from a scientific standpoint. Sipping on BCAA's or even through in Whey protein or an isolate into a peri-workout beverage is like if you were to drink BCAA's all day long. Your just constantly spiking insulin and MPS levels. I don't really see a major need for it especially if you are fed prior to training.
Could it help? Possibly, that would be trial and error on your end. Your best bet would be some fast acting carbs like HBCD with your BCAA beverage (starting low and increasing) and seeing how you respond and then adjust your dosage.