Migrate Easy --- Manual resize unallocated space won't work

I know I must be doing something wrong, but I cannot figure out what.

I am cloning a 750GB HDD to a 1 TB HDD. The old HDD has a service partition of 25GB, and the remainder is the main partition. I would like to end up with a 35GB service partition and an approximately 965GB main partition.

However, if a use the proportional option, I get an approximately 250GB service partition and an approximately 750GB main partition.

If I use manual, I can set the service partition to 35GB, but get a 675 GB main partition, with approximately 190 GB unallocated space.

Try as I might, I cannot add the allocated space to the main partition, or resize the main partition more than the original 675GB to include the unallocated space. I similarly cannot reduce the unallocated space to 0.

Any suggestions to get a 35/965 allocation on the new 1 TB HDD?

Thanks.