you can try to fit the same roof pieces into the gaps by using "free placing" and check if it looks good afterwards

i needed time to figure out rounded roofs for my round huts. sometimes snapping and partially needed to fit stuff in using free placement (holding left shift - deactivates snapping)

for me the third layer was the hardest to get right
the 4th and top layer was placed from the outside freely

edit: i also placed 26° corewood supports in the roof tiles after placing the first row. helped me a lot as support and guiding lines

https://steamcommunity.com/sharedfiles/filedetails/?id=2645773057
the 26° corewood poles snapped to the roof tiles

https://steamcommunity.com/sharedfiles/filedetails/?id=2632600700
the 26° corewood poles build up allmost to the top