Draw the left over into a clean syringe and inject into the bottle.
It doesn't matter if it says "intermuscular", there's no difference. The only difference between SubQ/Intermuscular is if you're injecting the same dosage then SubQ will give a higher increase in T over a shorter time and intermuscular will give a lower increase in T over a longer time. Just make sure its the same mg/mL in the bottle as your old vials and inject the same amount as you have been. If mg/mL is different calculate it so you're injecting the same number of mg as you were previously.
https://www.amazon.com/Vollence-Silicone-Mastectomy-Prosthesis-Transgender/dp/B08DHZPZ4N
I will say that they do run a tad big as I got the c cup model and I found the best fitting bra for me was a 36D.
So I also dont tuck, and I recommend getting underwear styles that have a bit more coverage than bikinis. Specifically hipsters, boyshorts, and briefs (granny panties). In the latter case, I've found that the extra fabric in the front helps keep things from falling out either side. You also want to look for brands/styles with a wider middle (gusset). I've had good luck with meundies hipsters (also they're so soft), but their bikinis and cheeky briefs are a bit less accommodating, and jockey briefs. A lot of girls recommend aerie, and you can usually find some stretchy briefs on amazon that have a wide gusset (ex: https://www.amazon.com/dp/B07RTGY62J?ref=ppx_pop_mob_ap_share and https://www.amazon.com/dp/B01HPTX94W/ref=cm_sw_r_cp_apa_i_i2SjFbDE9K4HM). It gets easier to find good underwear if you've been on HRT for a while, but these options worked well for me before I started as well. Good luck!