I find MAF pace rowing easier than MAF pace running and I get less HR drift which I interpret as slower depletion of glycogen stores.
Now most of this might be a personal exercise preference - as a 115 kg silver-back, me and running are never going to have a happy ending. But I don't see any good reason to treat the MAF rate differently for running or rowing.
Heavyweight blueprint rowers are 190-200cm weighing 90-100kg, roughly. Not svelte.
Bodyweight is the factor, when you have to fight gravity. 25-10 years ago, I liked to ride my racing bike in my hilly countryside hills up, and down and up and down and up and down. In that time period I was 75-78 kg and I have only two front chain wheels (I think nowadays three is standard). When 80+ kg I just feel having not enough gear to climb up, so I have not been riding really for the last years.
The same is with running. The last months I was 85-86kg, currently I am 83-84kg. What I can say for sure is that only one or two kilos less makes running a ton easier. Simple as that.
I recall a post by
@Harald Motz where he looked for a pace he could do all day.
all day, on almost any day. Something like this. When I go short say around 30-40min then I go towards my MAF, but otherwise...its to hard for me.