Spey casting on beach is difficult. It is better to learn on a pond or river. That said I learned in the surf because that's the only water I have local. OPST is the leader in this space. They have big followers and big detractors. It is a good starting place but may not be where you end up.
Spey is a journey. My advice is don't start it. I have flyfished for 50 years and with a 2 hander only the last 5 years. I own more rods and reels that I know and in last 5 years bought 5 2 hand rods and have nearly put away my singles. I'm a 2 hand junky and the "tug" is the drug. It is like the first hit of crack cocaine...you'll be back! That said you just don't need spey for the beach. You need the best overhead casting tool be it single or 2H and spey techniques can be very useful like it is easy to left line off the water with a snake roll regardless of what tool and line you are using. If you want to fish a river you need to know the character of the fishery at the time you fish. The clearwater right now is clear low and slow perfect for skating bombers and lil wangs to steelhead if there were about 75% less fishermen on it. The Trinity is deeper right now with classic runs and perfect for a floating line or a slow sink polyleader for muddlers under the surface or intruder.
So let's say you settled on a opst head choosen by using the opst online line chart for you weight and length of rod. A skagit head is always fished with a tip while a scandi ead is fished with a polyleader or very long mono tapered leader. MOW is the classic skagit tip and come floating, T8, 11, 14, 17 based on T8 at 8 grs/ft, T11 @ 11 grns /ft. giving you an idea of sink ability like a 1/6oz vs. a 3/8oz lead sinker. Then to fill in the gaps from floating to a solid 10ft. of T8 you get the funny stuff like 10ft. tip that is 5ft. of T8 and 5ft of inter.. Some people buy tip wallets with an aray of tips to fish any situation. Some guys are just dedicated to skating flies on top and only own floating tips. OPST on their charts recommend tip length based on grains of comando head and rod length and weight. Pick yout tip based on those charts.
https://pureskagit.com/pages/line-chart
Can you use an opst head on the beach? Yeah you can. Personally I don't think it is better than a rio OBS line but we all fish different ways. OPST heads are short enough that you will have way less problems learning their technique on the beach than you would with a long speyrod and a mid-belly speyline.