Surfing Waves

I have a 9' epoxy board that the shaper made with custom (he sanded down some larger fins) 6" high twins, Futures style. He is a big fan of twins and he wanted to make it as easy for me to learn to turn as possible. On a windy day I lost my grip and board fell on the sidewalk, breaking a fin. I am attempting to super glue + epoxy/fiberglass repair that fin. However, in the event that my repairs are less than successful, I would like to have (a) backup fin(s). (I don't want to return to the shaper because it would be my second time and the first time he seemed a bit annoyed. Probably a bad work-to-profit ratio.) I am 180 lbs., age 63, a 3 year beginner (have yet to execute a full cutback). I have surfed 9'2" NSPs on vacation, setup as both single fins and thrusters and found the thruster setup easier to use. I surf a shore break in Oregon and stick to below 6' days. Questions: 1) would I even notice the difference between an $11 single fin and a $75 Greenough 4A or equivalent? If not, cheaper is better, no? 2) Same question if I decided to buy a thruster setup. Is cheaper just as good for someone with my skills? 3) Should I even worry about fin shape? (Because I don't even know what I might like and the waves here don't seem to be good for noseriding--usually close-out quickly you see it very rarely.) 4) Can I put thrusters on my board, as my center fin box is 10" long. I.e., can any fin with a base shorter than 10" be put into a 10" box? I imagine so, but maybe I am missing something. 5) Should I get a single fin, rather than a thruster, in order to learn something new, like turning from the tail. Thank you!

I imagine northern Oregon would have strong winds, fin repairs of the sort you are attempting are almost always doomed to failure, the stress on fins is enormous the break will reactivate under pressure.
Thrusters were designed to make turns easier but a 2+1 set up can give you a good turning framework.Buy a genuine set of fins from Futures the centre fin be any formate that fits the centre fin box, centre fin between 8 to 9 inches. Often there are reasonable cheap,secondhand centre fins
Cheap copies Chinese ebay fins are subject to,failure or have to be sanded to fit plugs or boxes.

Go basic at this stage in fins as improving your skills underlies everything.Practice turning from the back of your board, don‘t get stuck in one stance learn to move up and down the board, stepping back to weight and drive a turn , not just lean turn.
Experiment have fun , if you can elsewhere from rapid breaking shore break you may get time to do stuff in response to a wave

I've surfed for years and honestly if I don't look at the fin setup. I wouldn't even be able to tell if I have a 2+1 or a single fin. The only times that I was able to tell was 1. I forgot to put on the single fin and only had the side bites. 2. The fin came loose and it slided all the way back to the tail. Both times it just felt really off, something was really wrong.

Random thoughts:
1) Futures Fins Thermotech T-1 fins should work and are budget friendly.

2) YES you can put smaller fins in a 10” center box. A tiny 2.5” trailer fin along with the T-1s will make for a Twin-stabi that you can adjust the tight/loose characteristics.

3) Single will teach you a lot. It will reward you if done right ( and punish you if you try to force it )

4) I don’t like riding Single in beach break waves.

Thanks everyone and thanks waikikichan for the specific recommendation. I found a place (Foam E-Z) that sells the Futures T-1 twin set and tosses in a 3.25" trailer. Bigger trailer than recommended but comes at no additional cost. I've ordered. Thanks again!

White board is a 8’mega magic I use for small/fat days or days I don’t want to work too hard ( ). Been using the FCS MR TFX Twins with a true Ames 2.5” center box fin. Really enjoy this board for those conditions better than I did with other configurations (including the also pictured cutaway side bite 2+1 on the red board which works better for me in bigger & hollower conditions).