Decoction questions

For my next bohemian pilsner Im considering a triple decoction. I'll use Weyermans Pilsner Malt (no other grains).
Considering this malt is well modified is a decoction recommended ? Im concerned it will affect head retention.
Traditionally decoctions involve removing a portion of the mash, boiling it and returning it to the MLT. I have a RIMS. Can I decoct simply by increasing temps as required or does the decoction need to boil ?

You would need to boil the mash for it to be concidered decoction, otherwise you're just doing a step mash. I don't think decoctions are really needed with most of the malts today. But, if you're doing a style that is traditionally decocted, then you should include it to keep with style guidelines. It does add a flavor that can't really be matched in my opinion. The closest you can get (in my experience) is by adding 20L crystal and not doing the decoction.