Pearson35.com is a great P-35 owners website. You can find almost any kind of project on that website, including lazy jacks which I just looked at. Having said that, I'm not crazy about the designs shown on that site. My P-35 already had lazy jacks when I bought her and I like my set up better.
My design has a line fixed to the mast about 3/4's of the way up. There is a block with a chafing cover that comes down and is about 10' above mid-boom when at an angle pointing to the mid boom area. A line is fixed to the bottom of the block. This line goes down to the middle of the boom where there is a block attahed to the boom. The line is re-directed towards the stern. It is fed along the outside of the boom to about 4' from the end of the boom where there is another block to redirect the line back up to 1st block above the boom. From there the line comes down to the boom about 5' from the mast where it goes through a block that re-directs the line towards the mast where I have a cleat (on the boom) about 2' from the mast where I can cleat the line. (There is a separate line for each side of the boom.) I've found it pretty easy to collapse the the lazy while sailing and easy to set up after sailing. (If you want actual dimensions I can get them for you this weekend, just let me know.)
Good luck with your P-35. It's a fun, sturdy boat with beautiful traditional lines (yes, I'm biased
). Just make sure you warn your guests that if you're hard to wind, expect some significant heeling.