I have just re-installed Baldur's Gate 1 and 2 on a new laptop and am finding that none of the fixes I was able to use with the display will work properly on the new system. I have always used the BGT.

Previously I could either use the widescreen mod and live with small menu screens or turn off 3d acceleration and play stretched fullscreen without the mod.

Now, no matter what scaling option I choose (I have an integrated Intel card and an Nvidia card but the scaling is controlled by the Intel one) if I play without the widescreen mod the game is surrounded by a black border but does not fit the border so some of the game screen is chopped off at the edges.

If I use the widescreen mod it only works at my native resolution, 1920x1080, which makes everything too small to see. Choosing another resolution results in the game playing in a small box in the middle of the screen also too small to see properly.

Does anyone have any advice?

You could try disabling 3D acceleration under 2D/3D settings in the bgconfig.exe. I was having a lot of trouble getting widescreen to work properly and for some reason that fixed it for me.

That is one of the fixes I was able to use previously but with 3D acceleration off it now results in the game screen being too big to fit within the black borders the game insists on playing within. I just see a chunk from the middle of the screen.

That's your problem, right there.

I've never heard of anyone using a graphics card and on board graphics chip at the same time without issues before. I have heard of it many times causing issues with games. Trying to divide it up with two different parts of the tasks, two different driver sets and hardware sets like that sounds like a disaster waiting to happen.