Copying your questions over here for easier answering.
Tim was diagnosed 2 months ago and we are still very far from being regulated.
Two days ago the PM preshot was low (124) so I stalled and gave his shot 1.5 hours late.
Yesterday he started off at 286 then spent all day in the 300s.
Today he was down to 103 AM preshot and is slowly dropping even though I didn't give him his shot this morning. It's just starting to rise now at +2 to 97.
Did I do the right thing in skipping this morning? I feel like his levels are probably going to go up really high this afternoon. I thought I might stall for a bit, but it kept dropping even after he was fed (I realise now that I shouldn't feed him if I'm going to stall, but that's pretty hard since he hadn't eaten since last night and was hungry). Could I have given him a reduced dose instead? If I do stall, I understand that the next shot should be given 12 hours later. What happens for subsequent shots - do you slowly make them earlier to get back on schedule?
I know it doesn't help that I haven't been consistent with testing lately, with having been away for 4 days then running out of strips.
His dose went up to 3.25 units before we went away, but I decreased to 3 units because he had been very low (down to 52) one day. After I got back and restarted testing the vet said to increase to 3.25 units again, which I didn't do until yesterday with being out of strips and with a low preshot number. My vet is a bit touchy about missing shots or changing dose without consulting her, but really it's impracticable to be ringing the vet up every time his preshot number is low.
The other issue I have is that I am plagued by small bubbles in the syringe. I know that I can tap to get them at the top and then squeeze these out, but that always seems to waste so much insulin, which is not cheap (I really don't have a choice but to buy it through my vet here in NZ). It's hard to get a consistent dose when the size of a bubble makes at least .25u difference to the amount of insulin in the syringe. Adding to this I only have full unit syringes (half unit syringes not available here) so the 3.25 is really a guess (just a fraction over 3 units).
Hello and welcome, I will tackle as many of these questions as I can. First, if you haven’t already, I would read the yellow starred sticky notes in the top of this forum. Most people here select one of the dosing methods described in the Sticky Note on dosing methods. Those methods will give you guidelines about when to increase or decrease the dose, and what to do when you get a lower preshot than you are used to. I printed off the Tight Regulation document, the method I was following, and gave it to my vet. It helped her realize there was some structure behind my dosing changes. If you are having to skip a lot, it may be a sign you need to reduce the dose by 0.25 units, so you can shoot twice a day.
Skipping was OK this morning. Over time and with data you will be able to shoot a partial dose, and even the full dose if you are around to monitor him.
To get back on schedule, you can move the shot either 15 minutes a cycle, or 1/2 an hour once per day.
Always have a backup container of strips around. I got nervous if I had less than 100 around, well actually, more like 200.
Syringes and bubbles, horrid little things those.

First, make sure you push the plunger up and down a few times to make sure the lubricant is spread around. Next, draw the insulin and about 0.5 to 1 unit more. Amount will need experimenting. Then remove the syringe from the cartridge or vial and draw up about 1 unit of air. Turn the syringe needle up. Tap the syringe to move the smaller bubbles up. Seems bubbles like to join other bubbles, and that way they will join at the top. Gently push or squeeze the plunger by twistinit, to remove the air at the top.