I assume you mean if you are on TRT, and not hCG monotherapy vs a TRT/hCG protocol. This depends on why you are using it. Really, two reasons, maintain fertility and/or maintain testicular size. If currently attempting to conceive, you’d want to stay on it. Extended use could desensitize the Leydig cells.
Dose is fine, hCH perhaps a little low. Typically see 250IU 3x a week or 350 twice. Some using hCG as PCT will take much more. Same syringe is fine and was commonly done years ago when it was injected with longer, larger, needles, but most use insulin syringes for hCG now.
I inject my T and HCG in the same syringe. Have been for just over 3 years. I do 400iu HCG then ad the T cyp. twice a week. That way there is no wasted T since HCG is the last to leave the syringe. Oh I use a 27ga 1/2" needle subQ in a love handle.
I take HCg because T mono made my balls ached all the time. With HCG no ache. I’m 65 and cut so no babies for me.