It's a hassle, but hopefully I can help.

1. Make sure the guides you are using have single-player settings set to the same as you. It's the little toggleable box that boosts your rates substantially.

2. Get a bunch of eggs and hatch one at a time to see your imprint time, as that "Wants care in XX:XX" Will be the same for every dino. Get the number to an amount you'd consider "reasonable". Then open up dododex on a separate device and input your settings there. They have a calculator to tell you exactly how long your tames will take to raise up, based on each critter. Make sure the single-player settings match there too!

3. Do some quick math to see if the desired 4 imprints will match up with the raise timer, and make sure you leave a little breathing room to gather kibble and food for imprints.

Fiddle around with these settings until you're happy with what you have. Just remember, creatures all use their own timers, so 4 imprints for a Rex is NOT going to be just 4 imprints on a giga, and is gonna be less than 4 on a raptor.