The 38 holds its "E" just as well as the pony and the F4, and can run the same speeds, it just takes a bit more thought in your angles and when to hit the throttles. I've caught ponies on the deck in my 38 before, you just have to have the right angle to dive in to work past any tightening of the controls.
You said you spent time practicing with the 38 on the deck all flaps out. That's great, but it's only one end of the spectrum of the 38, its high speed capabilities are the other end. Spend some time diving form 5k, 10k, 15k and you'll see the different times the compression comes in, make a bit more shallow angle and the the compression comes in later, or not at all. The "G" can rope as well as any, you just have to be a bit more sure of the enemy's "E" state