Hi Mikespeed , a couple of answers for you, often in transition from short to long the first few session you tend to bury the nose to about the length of your short board, it also sounds like you may have been a front foot surfer on your short board. The opposite is needed step back a little and try pushing down and driving with your back foot in the turns and guiding more with the front foot.
The angle for take off will still work especially in steeper waves.
Try for the angle paddling and as you pop up and get your balance try swinging a little top turn to straighten down the face and then lay over a big bottom turn FEEL the POWER that comes with this. Steeper wave and straight drops on a long board require a lot more skill in judging, it as you have so much more to get around.
One thing that is often overlooked about a longboard is that you can be on you feet already as the drop opens up and not have to take off in that critical zone of a shortboard
Get used to moving up and down the board and finding the trim spot where the board can constantly pick up speed. Learn to generate speed and use it and learn the secret art of the stall turn as explained above.
Have fun, the longboard way beckons
I've taken up troll hunting just for fun, instead of a rifle I'll just use a pun!