Welcome to the community Phemur.

I was in a similar situation as you. I had accumulated enough giftable levels (4 teams to 60) that I just created half of my 5th team on the master accounts, then did the paid character transfer to the referred accounts, then made the rest of my team on the master accounts and gifted them then. Granted, this cost me $50 to transfer the 2 characters so it might not be what you're looking for, but it's an option.

in case that was worded confusingly:

account a - linked to account c
account b - linked to accound d

(4 teams x 2 characters each x 29 levels = 232 levels saved)
* created new team members on account a & b, level them up to level 3 - 4 with new throwaway characters on account c&d. work of moments this way. then gift level them to 99% of the level, proceed to gift to 60.

* transfer new 60 team members to account c & d. create new characters on account a & b, level them with throwaways characters to level 2 - 3 or so, use throwaway characters giftable level to get them to 4-5. get them to 99% of their level. proceed to gift them to 60

congrats on your new team of almost 61 toons. not sure if this will work for you but this is what i did.

(alternatively, you can always just create new characters on your master accounts, and just gift them to 60. it wont be a full team but at least then you have alternative choices you can swap into and out of your team to meet different needs)