Basically, after experimenting with a few other settings (and being a longtime convert of Streamline's), Tomlong's advice turned out to be the best for my setup.
I haven't checked recently if Tomlong has got her new site up including all the flurry of notes.. But one for anyone using both Streamline and OSR...
As mentioned above streamlines fps limits need to be
within OSR fps limits (IRC 5-10% inside of OSR settings)
So if you have OSR min FPS at 10, then Streamline min fps needs to be 5-10% above that, say 15
Max fps I believe needs a further consideration. If for example you have OSR max fps at 45, then you would think Streamline max fps just needs to be 5-10% below that, say 42, but streamline also has another setting which adds to its max fps during combat (I think the default is 3). So during combat, if you have streamline max fps at 42 and streamline then adds 3 - streamline max fps then encroaches on the OSR max fps of 45. So for streamline max fps, deduct 5-10%
plus the combat adjustment from OSR max fps setting.... Simpler example for clarification below but obviously for those of you with cryogenic freezing methods bolted onto the latest beastly machines nether regions OSR max can be increased to allow a higher streamline max fps
OSR min 10 STR min 15 STR max 38 OSR max 45