Surfer and new board

Greetings to all, seeking suggestions from experienced, please advise, lake sailing much in the east, on 11' board bic model, Large sail that I can enjoy leaning into wind, new board smaller version and a two part mast on a very similar sail but cannot control or sail. It seems to me the stabilIty of the bic board is matched to the sail, and the newer board is very upset when I attempt to pull up the sail. Shorter board has the sail channel just about centered front to rear. Seeing big wind windsurfers on smaller boards in the west are flying catching big air on their ride, I feel as tho my new board is not matched to mast and sail. Or mast is ok but the sail is too big.
Any idea on what is my greatest misunderstanding of my issue on this smaller board, thanks many years surfing on large stabil boards in the Atlantic Ocean and lakes in eastern US.

I'd say its just a lower volume board to what you are used to riding and now the thing is much more unstable and tippy.

Whats the board ? how much volume ? what do you weigh ?

This all makes a big difference. What sail and mast etc are you using ?

Hmm that should be a pretty floaty board with your weight. If you're standing close to the mast, it'll be more stable. You want to be close to the board center. It may take some practice.

Sometimes, it's harder in light wind because the sail won't hold much weight. Are there other sailors near you that can help you out? You may need a little bit of rigging help?

Is the water pretty flat or are there small waves as well?

Thanks for the guidance, some understanding from advice, also what does my shortness have to do with where the elevation of boom. Yes on the big board I will always choose lowest mast position for boom. Also did find video of a guy dry start on a short style board, harness connection to boom, he was speeding way fast, his boom vert position was pulled to the rear his side of the sailing action. I feel when sailing upsail, swing sail parallel with board sailing as I lean back as far as the wind supports, I'm torqued into position positioning the mast forward to begin a tack or further towards stern to downwind. The old equipment seems to create a vent area near the boom tight cench location, the new sale when ringed seems to have a different area to vent the spent wind. Thanks for advice a smaller sale is not the answer a lower weight less float board, is the answer. Still I come away with the guy on video that is the placement of the correct sailing position to sail perpendicular to the wind. I know I'm over thinking smaller board much scuff grit if I ever get in the correct wind this board will fly. So thanks for all the guidance. Finesse and balance til the wind hits as far as lake condition, 5700 acres always some slight chop action on sailing wind and day drinkers riding their boat. I thought of a short mast and sail as that is how teaching a new to the sport person is instructed I thought. I remember how I was instructed by a new friend that saw me struggling on smaller lake, natural lake hard boated, a few years before was on Hamilton bay hotel room when I saw a woman with a Labrador on the board just coasting across the bay, I too have always been interested in goldens labs or many retriever types. So once I mastered control on a slow day on the lake I called to on of the goldens to join, sure enough she was leaning against my knee up til the wind took up to great speed, she would get up on her toenails and slide stern , I would drop the sale she would swim to get back on. Pull her up and off we would go, not great sailing action but a lot of pics were taken by local photo journalists. Not at all confident this will happen with this new style lofty board if I continue to attack it, which I am, this new lake although big does flatten overnight and som days. Not many surfers here in north east, mostly just crusty day boaters and too many ok boomer types. Like me, beautiful wet area salamanders and tree frogs, saw what I think is a grey fox two nights back. As you fellow sailers are responding in am being helped by advice, as you can tell I knowledge on equipment high volume board to sail requirements mast length, booms are all adjustable for length but this new set is the cam attachment style that is better than the big board boom tie on that I hated, I like ropes and knots as a puzzle type mind but all the cautionary too tight and it can crush the mast fiberglass,carbonfiber .

Yes it's true to the bone attention spans are down to 3 seconds not that knot heads have their nose stuck to a err uh smart phone that many times a day contribute to the smart phone wins making the one standing at attention look well stupid. Fun fun fun the only penalty I receive is when gusty wind ceases I fall off, but I always get back into action, damn fun gets into the way of social media foux news, be well stay safe

I think we have an AI computer trying to communicate with us!