Can you add more bac water to an already-mixed vial?

Quick question about a vial I already mixed. I reconstituted an 80 mg vial with 3 mL of bac water and the injections sting way more than I expected, so the dilution clearly isn't enough. I have pens and spare empty vials on the way. By the time they land I'll have pulled seven doses at minimum, 2.4 mg or 9 units each, out of the original.

Here's my plan, tell me if it's dumb. Take 1.5 mL out and move it into a clean empty vial. Add 1.5 mL of fresh bac water to that one. Then pull the rest of the original into a syringe, squirt it into the pen vial, then top that up with the same amount of bac water. Same drug, double the volume, so I'd double the units per dose to stay at 2.4 mg. Is topping up a vial that's already mixed a big infection risk, or is this okay? Stop me now if it's a terrible idea.

Yes, I used ordinary bacteriostatic water. I'd add .5 to 1ml on top of the existing solution, depending on my dose, the total mg in the vial, and the units I wanted in each syringe. A reconstitution calculator did the math, plenty exist. I think I ruined one pen out of 100 by pressing the button before the needle was in the syringe, an accident that occurs even if you never move it to a fresh sterile vial. I rushed it after doing it 50 times lol.

Pick your dilution first: 2.5ml of BAC for 60mg gives 0.5ml shots, and using less BAC gives smaller volumes. Pull that volume into a syringe, inject it into vial one, swirl until fully dissolved, draw everything back out, and squirt it into vial two. Thats it. The only downside is a small residue possibly left in vial one, too little to matter. Then write total mg on the new vial, BAC volume, concentration and the volume for one 12mg dose, so it cant be confused with your regular 30mg vials. I handle 10mg mots-c vials the same way, because a vial that yields 2.5 doses is awkward.

3ml of bac water goes in to dissolve it all, then I pull half out into one pen cartridge and the other half into a second, and top each up with another 1.5ml. Both cartridges get matched by color, the blue level, so I know each holds a similar amount. A bigger vial for the 100mg would simplify things, because GHK sometimes refuses to dissolve completely. Possibly next round I'll keep everything in a single cartridge, few people escape reactions like I have.