Couple things- congrats to going thru and getting everything fixed. That's step #1.
One thing that can help is getting your injectors cleaned, rebuilt, and balanced-After 190k, they may be pretty worn.
A proper tune- one for economy, not for power- can make a big difference.
Reading thru other's experiences is invaluable- Here is a web site that can help in your quest:
https://forums.tdiclub.com/index.php...el-economy.24/
Consider running highly filtered(below 1 micron) used transmission oil , either mixed w diesel , or you can run it straight, in tank #2. It's an old diesel trick, actually cleans and lubes your entire fuel system. You only switch to tank #2 when the engine is at full operating temperature.
Consider putting in the hottest thermostat you can find. Diesel's love heat.