Condi Alac: Full Ritualist or RR Viper?

[Faith.8912]

I'd like to hear from people who already tested Ritualist set on Alacrigade build, because that's what I planned to make (with full diviner power alacrigade on swap).
a) Snowcrows build in question: https://snowcrows.com/builds/revenant/renegade/condition-alacrity-renegade

b) Since i do not have Legendary backpack this is what i came up with using Diviner's backpiece: http://gw2skills.net/editor/?PmyAkeVlhQLsIajJRaMIKjBSjMBygjuk5TH-zRRYwBBKHdcfHScSgKVB5KE840sivKA-e

 

Questions:
1. Would i need more than 78% Boon Duration to keep perma alac? With regular condi food its exactly 78%, with concentration food - 84.73%
2. Can this build keep perma alac for 5 people alone or should I use full viper dps variant with RR (with second RRgade in same sub)?

3. Is ritualist a good open world (general pve, events) set in place of viper?

[ZeroSkitzo.5403]

1. No but 80% or even 84% is safer as with 78, you have to hit alac right off cd and sometimes you may not be grouped perfectly for it

2. Yes, see 1

3. I imagine ritualist is good for meta events but is pure condi so open world solo, will be slower than power. I’d honestly recommend celestial if you want an all arounder and has same boon duration as Ritualist. 
Good luck!