Benzol alcohol 2% or less is standard for preventing bacterial growth and benzol benzoate is the most common solvent most people don't usually have any issues with them. Some people like myself are very sensitive to ethyl oleate, it causes massive welts, painful limbs, and injection sites, for 5-7 days
Some people tolerate it well and have no issues with it. A person in that category is lucky because they can used very high concentration solutions of testosterone like 400mg/ml or higher. Less mls and less injections necessary if you use long estered stuff.
I get around the ethyl oleate issue by home brewing. You buy raw powders and mix, then filter the ingrediants to sterilize them, into a vial. Grapeseed oil is what I use for a medium, bought from any grocery store. Benzyl benzoate , vials, filters, syringes, scales and even steroid powders are all easily available online.
Lots of tutorials online regarding recipes for different steroids.
You can also cap your own oral steroids.
You have the added benefit that your gear is very cheap.