I don’t have advice really but a few notes recently from my experience and others, town water vs tank water definitely affects growth. A mate and I both bought a bag of Ultra Elites, I grew them for 5 hours in town water as I got home late and they are all 7.4-7.6mm. He grew them for 2.5hours in tank water and got some massive 8+mm gels but most were around the 7.6mm and a bit over that.
I also seen people have been adding bicarb soda to slow/minimise the growth of gels, but I have not tried anything like this. I like to be as lazy as possible with gels, 4 hours, 7.5mm barrels, drain, transfer to a dry bottle and let excess water fall off but not dry or touch them, and send it.
I have talked to a local tech and a speedballer, of which used white pearls, grown in hot water for 1.5hours. Hot tap water, hot enough you can touch it but cant keep your fingers in it… in a big mixing bowl, then grow. I haven’t tested it yet, but they have always had very nice Pearls and work well.
I actually grow/use very few ultra hards, as I believe them to be a potential problem in aegs, seen too many people with broken pistons and gears from a barrel stuffed with ultra elites. My goto gel for a couple years has been Ausgel Strawberry Milkshakes, now they say are an ultra hard, but are really only slightly above an armourtech, and still not hard enough for gas pistol use.
My main reasons for this is they are generally 7.3-7.4mm, pretty consistent, get 3 litres of gels once grown to a bag, and if I forget and leave them, they don’t overgrow. They also store well for a month or two after, so I can grow excess for the field, and then have plenty of useable gels for farting around testing at home.
Goat gels, seem to be the current preferred gel, and recommended by many. They grow in 1.5hours, then meant to be “rested” to harden. I found them best after a week of storage, but most are loving them a day or two later. I found them to be good, but really haven’t had much experience with them.
The original milkies are still good for most entry level budget blasters with no upgrades. An armourtechs are decent for slighty more expensive models. Though these are getting less relevant, my point is, gels are a use case scenario item as much as they are not a one size fits all.
My experience with all Ultra hards is they might as well go in the lawn a week later once the skin starts drying out, and if totally saturated are typically to big to be used a week later for the same reason. Generally I grow enough to use at a game day, and let them free on the lawn after a week or two.
Ultra hards, grow less, more often, they are not good for longer term storage gels.
In all, gels are cheap, buy a bunch and try them in things with varying soak times, if they dont work out they go well in the lawn lol!
I also found the Xforce predator v2 work awesome for wetech pistols that like undersize gels, and their snowballs are a good hard but not ultra hard gel for aegs. If I was located closer to them I would probably use their snowballs over the Milkshakes alot.
If you have an apache, ultra hards are really all you can use unless you want a good amount of crushed gel in your barrel ruining the potential accuracy of the surviving gels.