The manifest should help a lot, but it also depends on how you are sizing things. If you are using hardcoded twips values like 15, or using hardcoded pixel offsets, then a you need to rework your code if using a manifest. It's also important to set your manifest values correctly. Incorrect values won't help.

Without a manifest, the application should look stretched. With a proper manifest and not hardcoding twip/pixel values in any code where you move/size controls, then your app should look a lot better.

More details probably needed. A screenshot of before/after using a manifest would be helpful too.

P.S. 200% DPI breaks VB's DPI awareness, but not severely. As does any DPI where this calculation returns a fraction:
Code:
realTwips = 1440 / ((96 * DPIpct) / 100)
' DPIpct are values like 100, 175, 200, etc