Reading Research - ANCOVA?

I have a class (n=30).Using a variety of test I split them into stronger readers - SR (16), weaker readers WR (14) - Quasi-experimental

I chose a number of books for them to read according to their reading level (group).
I want to know which reading method (independent reading / guided reading better suits students vocab acquisition AND does one method better favor stronger readers or weaker readers)

Pre-tested targeted vocab

1. Students read book with no help guidance (10 days)
2. students read second book with help - tasks, worksheet etc
3. students read 3rd book with help etc
Post test vocab books 1 and 2
4. students read 4th book no help

The books with no help let's call IR (independent reading) and the books with help R+.
So I have measures pre and post vocab tests for
IR after 14 days for SR / same for WR
IR after 28 days for SR / samefor weaker readers

R+ after 14 days SR / WR
R+ after 28 days SR /WR

So I used a T-test first to determine if SR made a vocab gain and seperate T-tests for each group.

Now I want to compare SR/ IR with SR / R+ (14 days) etc
(which method is better)

and compare SR/ IR with WR / IR
(Is one group better than the other for this type of reading)
For this I used an ANCOVA with the pre-test as the co-variate.

Do you think this is okay? Is ANCOVA right?