Timing vs Valve Lash????????

Having the valves loose is like having a smaller cam, the valves open latter and close earlier and have less lift. The norm is as the cam get bigger you need more initial timing not less. However, the difference in your situation is very small so I wouldn't think a change in timing is warranted.

BUT, if the car is not running as well now I would be concerned that you have some of the valves adjusted too tight and they aren't closing completely.