Sometimes it's better to admit you're wrong and just move on, rather than dig your heels in. Not always, mind you, but sometimes. Just sayin'.

Sylvan Library is suboptimal and redundant. You don't run a suboptimal/redundant card in hopes that you will happen to have another particular card in play at the same time, especially when that particular card is just fine by itself.

If you really want to devote extra slots in your deck to making Coatl bigger, just run some more cantrips.