I'm not entirely sure about this but if I had to tackle that first tuplet, I'd probably do something like this:
As far as I understand, a 7:5 would be a septuplet within a quintuplet so you would work out the lowest common multiple of 7 and 5 which is 35. Now, imagine the tuplet is split into 35 equal parts. Every 7 parts=1 quaver of the quintuplet. Every 5 parts=1 quaver of the septuplet that is contained within the quintuplet (the actual quaver that is notated on the page.) If you look at my drawing, you can see the 35 divisions in the middle with the quintuplet quavers underneath and the septuplet quavers above. Above the septuplet quavers, I've written out the first tuplet from your example.
Obviously this would be very time consuming and impractical and you would have to learn the tuplet very slowly as if it had 35 "beats", though I can imagine that over time you'd get an intuitive feel for the rhythm of a 7:5 or 5:4 or whatever and be able to get through it relatively quickly.
Like I said, I'm not 100% on this; that's just how I'd go about it. Common sense tells me there is a simpler way but I don't know what it is.