I use epoxies in the furniture repair part of my business also and frequently need just very small amount. Since the epoxy works well on a volume basis, I use a small straight sided(very important) container and just measure the resin and hardener into that in the appropriate quantities.

for example, with WEST and it's 5-1 mix, I mark a thin stick at a 5 unit point, then make another mark at the 6th unit. I usually use 5/16 and 6/16; or 5/8 and 6/8ths. Pour the resin (I use the pump) to the first mark then add hardener to the second. With MAS I use a 2 -1 range - i.e- say 1/4 then 3/8.

The secret to small quantities is the container. Look inside the plastic top from a can of spray paint- you'll see a very small straight sided section in there- cut that out using a band saw or what ever. You will then have the container to then mix some where around a teaspoon full, quite accurately. I've used this method for many years now. Just be careful to hold the container level and pump very slowly so you don't go past the lines. And when you are finished, if you'll turn the little cup over so the epoxy can drain out, once it's cured you can peel the left overs out really easily and use the thing over and over.

If you use empty tin cans, you can use the same method to prepour quantities of resin when working on a larger job. Set five or six cans of just resin out, ready to have the hardener added. Then when you need more, just put the stick in, pour hardener to the correct line, stir and go. Stick can be reused over and over since there is no cross use - it's just going into a can that you are gonna stir up anyway. Quantities then depend on size of can and units selected.