How to create and draw graphics

[LCD]

what if I wanted to create a second UDG
Would I change the 23675 number to something different?

23675 is the Spectrums system variable address which holds the address of the UDG set. Changing this number will result in a high crash probability or strange bevaviour. You can define another set of UDGs called e.g. secondudg() and use their name in place of udg()

Also, do you know of a speccy emulator that accepts commandline arguments and can load a tzx file in quickly?(not spectacular)

Ive found 2 emulators but they only do one of the above each :x

I use ZX Spin, it is not Spectacular but loads TZX generazed by ZXBC instantly. In other emulators maybe you can set the loading options to fast/flashload too. And I think, almost all Emulators support commandline arguments.