I Don't Buy That Argument That 730's Cause Stretch. Why You Ask Cause The 1st Gen Area51 Multi Colored Panels Came With 9 Watts Of Far Red And Was On The Entire Growing Cycle And Nobody Complained About Stretch. However They Did Think That They Received A Defective Panel Cause It Had 9 Bad Leds Until It Was Pointed Out That The Leds In Question Were 730's.In My Experience A Plant will Stretch Because The Light Is Weak And The Plant Will Stretch Up To Get More Light
Id agree with you on extra far red not causing stretch if its balanced with the rest of the spectrum. Ive never done far red EOD myself but some peeps have commented on extra stretch. The thing here is having far red on and nothing else on.
Randomblame quoted 3000-4000 umols per m2 for EOD treatment: a good far red is about 3ppf/w, that would be roughly 100ppf per second for OPs 35w. With so much wattage you could get it done in 3000/100=30 seconds. The 14.5 mins extra wont really do anything to the plant except for possible stretch.
Obviously there are many things that lead to stretch or its inhibition, ive seen a few peeps with uv and far red on thru the whole day with no real stretch.
If you have to do EOD with 15 mins intervals (analogue timer) i would rec Aw16 way, get it on a little before the mainlight turns off. But doing this it would be ideal with something like the sonoff system where you can get all your timers synced together, too much guess work if not.