10 into 10 unless you are running grams per week.
The sketchiness/materials of construction issue with spikes was covered in another thread. I would never use those and they aren't intended to be used with the oil based injectable roids we are talking about here.
This thread sure took a turn.
Just posting this here in case it helps anyone.
I found this Vial Adapter which I expect will help me reduce the number of drawing needles and improve dose measurement (specially when mixing oils). Once placed in your vial, you basically connect your luer lock syringe and draw as needed. If you're interested, search for 'Multidose Vial Adapter', there are also a few videos on how it works which made me give it a try. For your reference, I'm in the US and got 6 of them for around 20 bucks, shipping included.