Dick,
Yes. I taper the blocks to fit the TE sheeting for about 3/4 inch. Beyond that, the size becomes pretty excessive. The 3/4 inch has served me well and I've never had one come loose. I think the important point is to glue them securely to the rib. That allows the stress to be directed to the rib which is much more solid than the TE sheeting.
Charles,
The plane is a Continental, scratch built from Tom Dixon plans. The styling is beautiful, but challenging. I've had to plan well ahead during the build to assemble the pieces in a logical order. A fun airplane to build. Planning an O.S. 46 LA for power. Biggest challenge so far has been the cowling. Looks simple on the plans, but a bit of a pain to make it fit the O.S.
Paul