I will second what pussuskattus suggested...although it is definitely more work/time, we found that it was very worthwhile to mock up the drawers and try out our handles that way. We ordered various sample sizes of our handles and DH cut some scrap wood planks in the lengths of our drawers. We then just placed the handles on each board and it was VERY quick and easy to determine which size to go with. It was surprising what we found...definitely some different outcomes than what we had thought before mocking up. There would be no need to cut wood, though...could easily just use posterboard or scrap cardboard from a shipping box. And the ribbon idea would be easy, too. Would save the step of buying the pulls if you don't know for sure yet what you want. Good idea for next time! Good luck with your search on the vintage pulls!

I just went through this - I ordered my pulls the other day and they are now in transit. I meant to get this figured out before I got the cabinets, so everything would be ready, but I procrastinated until the cabinets were in. And I am glad I did. I mocked up the handles using silver ribbon and double sided tape. My initial guesses about what would look right were wrong, so I did a lot of fine tuning. For the drawer pulls, I went with lengths slightly less than the panel in the drawer. (I have shaker paneled drawer fronts. The answer would probably be different for slab fronts.) But it was tricky because the pulls don't come in all the lengths that I wanted, so I had to compromise on some, between too long and too short. For the door pulls, mounted vertically, I thought about full length. But then I realized a problem with that. For upper cabinets I wanted the bottoms of the pulls to be a fixed distance from the bottom of the door. But then the top ends would not be a fixed length from the top of the cabinet because they don't come in the right lengths. I ultimately decided it would be better to make them all the same length. And after trying various things I settled on 10". I think this worked best for the set of cabinet heights I had. I used the same 10" on the lower doors, aligning with the top of the door. The exception was the pantries, which have a tall lower section and a shorter upper section. There I used the 10" length on the upper, but a long one (28") coming down from the top of the lower door. I did that so that there would be handle at a convenient level for the people in my house. Bottom line - I recommend waiting till your cabinets are in so you can really visualize what the pulls will look like.

http://theknobbery.com/cabinet-hardware-sizing-guide

-Thanks reeny. That helps a lot. I'm assuming you like the look of two different sized pulls since they are each proportional to each door vs having two of the same sized pulls on different sized doors.