Quote from: RedMana on September 03, 2017, 02:52:29 AM

1. Would most people consider that client trustworthy? Is it OK to let it directly access a copy of my regular wallet?

things you should be asking are:
- who has made the code, and who is maintaining it
- is it peer reviewed enough to know there is no shady thing inside
- is it tested enough to see there are no bugs in it
and since you usually don't compile the source code but instead download a binary
- is the binaries safe
- who is making them, and are they trustworthy (for example last time i checked electron cash binaries were made by an anonymous person)

Quote

2. To avoid having to downloading ~140GB of blocks all over again, can I copy the blocks and chainstate folders from my regular client? Or will it get confused if that contains blocks passed the split date?

yes you can. but you will still have 2 separate >140GB folders with the total above 250 GB if you want to run both full node clients.