Hi, I just posted a thread on re-testing. We "had" to test my oldest dd at 4-10 for school application processes. She only got English from the environment, preschool, etc. We KNEW going in that her verbal scores would be an underestimate. It was just hard to tell by how much.
In a couple of months, we'll go the same route with my younger one. She's had more hours of preschool...
I guess, your DD will have to be at a "reasonable" level in English for you to get a decent guess. My DD6's leap verbally was pretty significant (jumped from 92% to 99.8th percentile).
I have heard that kids need to have at least 2-3 years of regular, full day school to catch up. We tested my DD, for the second time, after 1 year of K and 3 days of 1st grade; so this second time around is probably still, technically, an underestimate (although in practical matters it doesn't really matter).
Then, there there are better tests for less verbal kids (and bilingual kids in general would probably count as that), so the SB5 is a better choice than the Weschler.