One full dropper is the mg on the bottle then you just divide it. So if the bottle says 50mg then 1 dropper is 50mg, half the dropper is 25mg 1/4 dropper is 12.5 mg. This is just an example
I would honestly add s4 into the stack if at all possible. It will help a lot with your fat loss, strength, lean mass, and hardening. The vision sides are dose dependent, so they are easily controlled and generally that side effect is blown way out of proportion as well. The stack I would recommend to you is this
1-12 S4 50 mg day... split doses... 25 mg in the a.m. and 25 mg in the p.m.
1-12 GW-510516 (CARDARINE) 20 mg day… dosed all at once 30 minutes before workout…
1-12 mk-2866 12.5mg per day first two weeks then 25 mg day dosed once a day in the a.m.
1-12 SR-9009 30mg per day (5mg dosed 6 times every 2-3 hours)