Please, you do not need to move on to injecting.
I tried it and thankfully stopped.
Injecting will fuck up your veins, which makes your arms or where ever you're injecting hurt, thus making you want to injecting more cause of the pain.
Add to that the cold feeling in your hands, arms, feet and legs you get from damaging your vascular system and that morphine (Which is in street Heroin along with diacetylmorphine and 6-monoacetyl-morphine and other opiates from the opium and acetylated forms of those opiates, cause it's not manufactured to pharmaceutical grade.) releases a load of histamine and opens your capillaries, thus making you feel warmer and along with the pleasure it creates a bad feed back loop making you want to do it more.
As a long-term user you're best off moving on to snorting, it's as affective as intramuscular use and causes a good rush, cause you can get a bigger dose up your nose and in a quicker time compared to smoking.
Smoking is noisey, smelly and you need more time and equipment to do it, meaning you're more likely to get court if you can't do it in your own time in private.
Yes, Afghan #3 can be snorted as it comes as diamorphine freebase, which is what Heroin #3 is, is fat soluble and shortage.
I imagine cooking it up in to Heroin Citrate (Using Citric Acid.) or Heroin Ascorbate (Using Ascorbic Acid/Vit C.) and then boiling/evapourating off the water, leaving only the Heroin (And cuts if you didn't use a Micron-filter.) would probably mean it'll be more soluble but I'm not 100% sure on that.
I know if you used hydrochloric acid to make Heroin Hydrochloride it definitely would be but that'd be more of a pain to do compared to the other two salts mentioned.
If you're not used to snorting anything you may feel the need to sneeze, especially as the histamine release can do this, but with repeated use that feeling will stop.
Honestly try snorting before injecting, nothing good apart from the short lived injecting rush comes from injecting and the rush is better from snorting than the feeling of smoking.
When using a T-shirt (1.5g, yes I know they're meant to be 1.75g.) I can stick around half up my nose (Obviously a quarter of it all up each nostril.) in one go, so the rush from that is far better and hits quicker than attempting to smoke it all quickly and getting it to breakthrough my tolerance so I feel high, which I can't do when smoking.
Go easy, as you can OD when snorting.