Unsure if VNC is still in active development but I figured I should submit this issue for reference.
As noted in title, these issues manifest with ServUO Version 0.5, Build 7517.31796 and the latest version of VNC.
Client
ClassicUO Version 0.1.4.43
UO Version 7.0.75.6
Changing the toolbar position only works intermittently causing the grid to be significantly smaller than intended. See image:

Sometimes, when logging into the original classic client and loading the toolbar, the grid will cover the entire screen as intended. This is not 100% repeatable.
In addition, when attempting to resize the toolbar gump to any value other than the default, nothing happens. Using only accepted format of {0},{1}.