There seems to be a big difference between Gohan and human (M3) and we know that Gohan (M3) had a power of 10,000. Tenshinhan in this film is still higher than Krillin. Honestly though for years I have not seen the film but had to Tenshinhan 9,000 power.
He should be considerably lower than Gohan since Gohan was able to beat one of the twins rather easily while Tien couldn't (I haven't seen the movie in a while so I may be wrong). Lately I've been re-evaluating where I should put Nappa. I used to have him close to Goku's 8,000 seeing as he was able to put up a decent fight against him but now I think I may put him in mid 6,000 range at best. I put he Z-Fighters around that mark in the movie. So I give this to Tien.
Gohan didn't really defeat the twins, since, later, they showed up unharmed. Also, Gohan's massenko was
evenly matched with a twin's blast. So, i place the twins at 10k for simplicity, which means Tien is a little
lower than that (9k-9.5k)