I would like to ask how to use more than one core installation at the same time. It looks the new version is portable so all the details are in the dir I wanted it in, no data somewhere on C:\. I know there was the -data-dir flag which seems to be still working though I'm not sure if that's what I search for. I do not want to interfere the different wallets with each other. I just want to save disc space by using the same files of the blockchain. -loadblock doesn't sound like that also, I do not want a copy of the blockchain, I want multiple wallets use the same blockchain storage files. How to do this?
You can't. Bitcoin Core does not support this yet, although Multiwallet functionality is in the works.
Second question, I searched for an option but didn't found it. Core creates reserve addresses though they are invisible. When exporting the addresses I only can see the visible addresses. I want to do 2 things, make all reserve addresses visible so that I can export them
I don't think you can do this. You can export all of the addresses using the
dumpwallet RPC command which will export all of the private keys to a text file wherever you specified.
and secondly I want to raise the amount of reserve addresses. How can this be done?
Add
keypool=<n> to your bitcoin.conf file where <n> is the number of keys you want to have in the keypool (aka reserve keys) at all times.