I do not know about the 103 or 107...
From flowing the heads only that the TG1 I have flows great!
The jt123 is a good flowing head too...the 3 jt109 I have flow pretty crappy compared to the TG1,or the 123.
The jt97 head I have also flows pretty bad...
This is just the results I got from flowing them not dynoing them.
A stock gx200 head flows a smidgen better than a jt109.
And the few gx160 14cc heads stock flow the same as the jt109.
Slightly touched up Honda 14cc heads outflows the TG1 head.
Slightly touched up gx200 head flows awesome at low lift .150-.250, then flows the same as the 14cc at .250-.350 lift.