If the growth of these bodies is fractal, with their porosity increasing as larger porous bodies collide, their radial drift timescales become long, allowing them to grow until they are compressed by gas drag and self-gravity forming small planetesimimals.
If the growth of these bodies is fractal, with their porosity increasing as larger porous bodies collide, their radial drift timescales increase and their growth timescales decrease as their surface areas increase. Inside 10 AU thia may allow them to grow until they are compressed by gas drag and self-gravity forming small planetesimimals.