1. IMO, Epi's sweet spot is 40. I wouldn't wait until the last week to bump to 40. Personally, I'd run it either 20/30/30/40/40 or 20/30/40/40/40, especially since epi is all you're using on this cycle. 2 weeks of 40mg vs. 3 weeks of 40mg will be determined by assessing the sides you've experienced by the end of week 2, and either bumping to 40mg (no sides observed/very mild sides), or staying at 30mg for one more week (side effects affecting you pretty noticeably).
2. Yes you'll want an "estrogen blocker" on hand during your cycle. "Estrogen Blockers" are called Aromatase Inhibitors, Adex is my personal preference. It's prescription-grade, and assuming you're using a website I would suggest buying it along with your SERM (the site you buy from will likely have both available). Take it if you feel you have any gyno flair up. I recommend taking some as you come off your SERM at the end of PCT as well, just to ensure you protect against rebound gyno.
3. Start PCT the day after your last epi dosage - epi has a short half life and clears your system pretty quickly (hence having to take it every day). Most people who start a cycle on a Monday are going to have their last dosage on a Sunday 4-5 weeks later, and start PCT on Monday. Clomid I like 100mg for the first 3 days, then lower it to 50 for the rest of that week and the next, and then take it down to 25 for two more weeks. If you don't feel fully recovered, you could put in 25mg for a 5th week.