I think he was considerably weaker. Roshi said that Tambourine was strong enough to kill Kuririn, instead of focusing on a weakened Kuririn... So even if Tambourine couldn't have done that so quickly like he did, the apparent way he did it was enough for Roshi to conclude Tambourine was considerably above Kuririn anyways. How much is anyone's guess. Maybe as strong as Roshi... Or in the same realm.
Remember Goku using his full match level was enough for Roshi to conclude Goku "may" have surpassed him already... And Roshi was surprised about a battle level even existing, suggesting a considerable gap between full power Goku (22nd Budokai) and Roshi.
Like:
Kuririn/Yamcha : 100
Tsuru : 120
Roshi / Tambourine : 139
Full Match Level Goku : 145
Tenshinhan : 170
Goku (full power) : 180
----
Drum : 225
Old King Piccolo ( < 50%) : 280
— FP : 600
Young King Piccolo : 1,000
[That keeps the power gap between Drum and Tambourine roughly the same as the gap between young King Piccolo and old King Piccolo]