You could run just two bottles of 10ml and hope you have exactly enough to take full shots for 10 weeks. My experience has shown that realistically I can hope for 9 and 1/2 shots per bottle when using UGL gear. Sometimes I do get a full 10 and occasionally I get 10 and 1/2 shots. I think you should get three bottle like Iron suggested and push you cycle out to at least 12 weeks. Really with enanthate or cypionate the minimum length should be 12 weeks. If you get three bottles just run them until they are out that should get you close to 13-14 weeks which is fine. The enanthate ester doesn’t really sing until like week 7-8 so 10 is just not enough time to harness it properly.
For the AI I would get the arimidex when you order your stuff. I would not just start running it, this is your first cycle so see if you even need it at 500mgs a week. A lot of guys don’t need it and it is all to easy to use just a little to much and make your gains go no where, as in no gains. We need some Estrogen just not too much or too little. You need to do some experimenting on your first few cycles to see what exactly you do and do not respond well to. If you do end up needing it I would say start with 0.25 mgs on days that you inject but you will probably need 0.5 mg on days you inject. That seems to be the dose most guys do well with when running 500mgs a week.
If you do end up needing the arimidex just know that by two weeks after you stop injecting whatever dose you were using will be way too much. Really you might not even need it the first week after you stop injecting or if you do need it you will need a reduced dose.
Don’t fluctuate your dosing just pick one and stick to it. The enanthate ester doesn’t allow on cycle dosage adjustment. By the time the new dose finally stabilizes you will not have enough time left to really see what it does. If you are confused about why go read up on the half life of the enanthate ester. Hell just go read up on half lives period and then look at the different lengths of the different esters. The general rule is it takes about five half lives of steady injections for that dose to finally stabilizes in your blood then it takes five half lives after you stop for it to be completely clear of your system. Just fyi being clear of your system doesn’t mean a drug test can’t detect it.
For you needle choices, I only know gauges so mm doesn’t translate so I can’t comment. If you can convert it I use 25 gauge either 1 inch or 1.5 inches long. That seems to be a good all around size. It lets you draw from the bottle fast enough and then it keeps you from injecting too fast. It kind of makes the whole process some what idiot proof.