Q - My 53:11 is 76 gear inches and I max out at 45kmh on the flats... and it is really set up fro cruising in the 25-30kmh range all day.

I'd set up that 11-34 with a 36 tooth ring if I was going to be doing any hard climbing or towing, the 42 would give you a pretty excellent range for almost everything.

Have set up a fair number of 1 by x drives for folks who have no need or desire to be shifting an fd.