1) Actually, you can get by with less on a more frequent injection protocol like E3D. You will have much more stable levels, so your lows aren't as low. Therefore, you can get by with less. Also makes for much more stable and lower E2 levels in that you don't go super high out of range early in the injection cycle and drive faster conversion to E2.
2) Regarding the exact dose, I suggest you start with 0.2 mL and see what your labs look like in 4 to 6 weeks and then adjust from there. Everyone is different and it is highly dependent on SHBG levels. I have very high levels, but I bring that down into range with either low dose Winstrol (10 mg/day) or low dose Anavar (20 mg). Which keeps me in the zone. I find that when I'm in the zone, that 0.2 is adequate and 0.25 is on the high side.
3) I get all of my syringes from TotalDiabetes.com. Here's the exact syringe I use:
https://www.totaldiabetessupply.com/...g-1cc-1-2-inch. They deliver via USPS in most states, fast and easy. It's a 1/2 inch long needle and it works just fine with the quad muscle. For me, I know it goes into the shallow muscle (I can feel it). It's debatable too whether there's any difference between IM or SC.