I did Outlaw last year and ran 10 miles on the saturday afterwards and a 40 mile fastish club ride the next day. Felt really good. If you've been training/racing for years, reckon you'll be fine. If you're a newbie and have a newly built base, give it a miss and concentrate on the Outlaw.
Done the Worthing Oly for the last two years. Great race. I will miss this years as doing the Outlaw on the same day. The early start means the sea is generally flat (was the last two years), bike course is fast with no nasty hills, just a few long drags. Raw Energy Pursuits who put on the race are great, as are the local tri club Tuff Fitty Tri Club. Enjoy.
In my opinion, it is relative to speed. The faster you run, you will naturally begin to land on the mid to forefoot area. If you run at say 10 min mile pace, you will land on your heels. The problem comes when people 'try' to run a certain way. If you watch someone running at a slow pace and landing on their forefoot, it is imo the most rediculous thing ever. Young children naturally run with excellent form, they don't think or learn it, it is instinctive. Again imo, the key thing is for your foot to land directly underneath your hips. Speed will naturally dictate whether the heel, midfoot, or forefoot lands first.