I have done a cycle with and I'm not proud of it but all my fish lived.
You have to check your water twice a day. There are going to be times when it will spike and you might need to do 2 water changes a day. Keep the ammonia no higher then .50 .25 would be even better. Some days you are going to have to do more then a 20% change.( when did 20% become the only amout of water you should take out?). Yes you have to do water changes every day some days when my levels were high I would do a 50% change to get the ammonia to .25 . You should never go a day without doing a water change you will run the risk of your tank getting out of control.
Also do not feed your fish every day. Only a tiny bit once every other day. If you notice a big ammonia spike hold off feeding for 3 days.
So you are going to have to do that till the nitrates start to show up and that is a week or so after the nitires go down.
Sum up
Check water ammonia and nitrites in the AM and PM.
Do water changes everyday as needed to bring down the ammonia to a safe level of .25 or .50 Never higher then 1.
Feed fish less.
And just keep that up till it's done.
Cycleing with fish is stressful on the fish and you. It's a lot more work. I'm doing a fishless cycle now for my 55 gal all I do is add pure ammonia check my water every now and then add more ammonia if it gets low and wait. I will never do a fish cycle again.
If you have hardy fish and stay on top of your water your fish should live. Good luck.