Hi Standard Freunde

My old Rex 350ccm have been missing it's engine for many years.
Now it's much better, thanks to Tim !
The new engine seems to fit ok.
Still I miss the primary chaincase, the complete ignition points unit, exhaust system, speedometer, well most of it, and some other minor parts.
I have some spare parts for other Standard models from the last part of the thirtys, if any of you want to excange something with me.
I am wondering about the performance of the Rex because I have seen 12 PS with 1:5 compression,16 PS with 1:7 compression, 18 PS with 1:6,5 compression, and for the "Rekord" 24 PS with 1:9 compression.
So, what would be the best choice ? Will the Rex engine blow up with 1:9 compression ?
Was there any other changes to the engine from 34 to 39 that makes the engine performe different ?
Was the Rex ever made with low exshaust system ?
I now you like pictures so I try to include one.
I understand German text to some exstent, but find it very hard to write, so just go along with German.
Any coments ?