I've got it faily easily in that genetically, I'm not designed to be small. I have 4 siblings, 3 of which are all very large as well, and it runs in my structure. On top of that, I gain weight VERY easily at times (not always, but usually this is the case) and I can gain on as little as 3000 calories/day. For a person my size this is very rare, but my metabolism is naturally slow so just by eating normally without stuffing myself I can keep weight the same, and all I have to do is toss in an extra meal to make sure I have enough in me to put on weight. However, most of the best gains have been through continuing to just work on compount movements with lower to moderate reps (1-8 at most, usually 3-5 reps per set), even though this often goes against what most "science" has to say about the best way to gain. If I can give any advice for most people, it is just to always remember the following points -
1. Eat more than you think you need to (unless you've got a freakishly slow metabolism like me)
2. Always do compound exercises for your main focus, leave the isolation stuff alone unless you're planning on bodybuilding. Also, if you can do a lift standing up, do it that way! (this applies particularly to overhead pressing)
3. Squat, deadlift, squat, deadlift...repeat as necessary. Once I started doing those two things I broke past being stuck at 240 and added the remainder of the weight quickly.
4. Never forget to get enough rest, and do all you can to keep stress low. That's my biggest problem now - stress is terrible for me, and it takes all I've got to feel calm on most days. If I'd been stress-free this past 2 years I'd probably have another 10 lbs. of weight on me by now!
5. If whatever you're doing for lifting has slowed down or stopped making gains for you, quit doing it and move on! People get afraid to experiment, which is the worst thing. Yes, I get stares from people wondering why I'm squatting over 700 lbs. but only moving the bar for a 6" range of motion, but that's purely because they think that if you're not benching or curling that you're not doing things right. Play around with odd lifts, start lifting anything that's not nailed down when you're out and about, and again, don't be afraid to do stuff that looks weird to everyone else because sometimes it's the odd stuff that will put you to a new level.
I know that you've been doing a lot of deadlifting and overhead lifting, and keeping with those two things will definitley be what pushes you on upward in weight. I can't remember if you do a lot of squatting or not, but if you aren't definitely get on it! I swear, if someone wants to add 10 lbs. in a hurry, just chain them to the squat rack for a few weeks, feed them plenty of food and it'll all get done in a short time. Squat heavy for singles and doubles, squat moderate weight for sets of 10 or more, do squats starting from the bottom way below parallel, do 1/4 squats with 200 lbs. more than you can full squat....all these things will work to push your body into weight gain better than anything else I can think of. It isn't called the "king of all exercises" for nothing! If you squat and do different varieties and leave all you have at the rack and come away wiped out from giving it 100%, you won't regret it one bit.
If you can't already tell, I love squatting
I used to hate it and keep doing leg presses, but once you're humbled by squats you never turn back. It doesn't mean much if you can leg press 1300 lbs. for reps (like I once did) if you can't squat 250 lbs. for a set of 5.
You've definitely made a ton of progress, Jonathan, and I think that if you keep on doing what you've been doing you're going to go a lot further. Just change things up periodically and it'll all come in time. And, with that frame of yours, I recommend getting into strongman at some point, too - height is a distinct advantage in many events, and with your size you might just find your calling!