The cost of the bigshot head itself is only 50 or 60 dollars. Yea, go shopping, source the heavy duty surgical tubing, find the aluminum or steel, figure out how to form the base so it'll plug into a pole, find a sewing machine, figure out how to sew the pouch and from what material you'll make it from and how you'll affix it to the rubber tubing.
You should save yourself a ton of dough.
OR, go out and do an hour or two of tree work, or haul away a pile of brush or whatever. Call Sherrill on their 1-800 line as soon as you earn 60 dollars, order, and it will be on your doorstep in two days. In the meantime, work the rest of the day. Then work tomorrow. By the time the bigshot arrives, you'll almost have forgotten you've spent the money.
The bigshot should then allow you to access canopies more swiftly, making more efficient work of it all, eventually paying for itself in time saved and then once it's paid it own self off, it keeps giving, and giving and giving.
In my book, this is called an investment, rather than a purchase. Any other investment that guarantees this kind of returned would be swarmed on by the investors, but to complain about the price of something that's under a hundred bucks that makes your worklife easier, and then figure out how you can spend a bunch of time to reinvent a wheel just to come up with some mutant form of an otherwise affordable, professional, world-class device.....
I'm sorry. I'm painting my past, ten years ago before the BigShot was invented. Golf balls, baseballs with eyebolts, different lines, hand slingshots, bow and arrow, crossbow, water balloon launchers and yes, things that resembled a hyperdog. I've also used decoy line, good luck on rough crotches or even smooth crotches when recently rained on.
What a bunch of frickin wasted time I spent, but at the time there was nothing specifically made forn the purpose of shotbag launching. Once I got a bigshot, life changed. It outperformed anything I'd tried previously, by a large margin. Once ZingIt line came out, I could pack away the clumsy 1/8" polypropylene slickline. Once I quit using awkward pickle-shaped throwbags and spent the extra 5 or 6 bucks on the streamlined and lead dust-free harrison Rocket bags, much better. With a shotline reel for tangle-free shots, superfast rewind and compact storage, the system is complete. The choice then is 'which bag weight to use?'.
Granted, that complete system including pole, line, BigShot head and shotline reel, getting up near $200.
Still, it is an investment, and not a really big one compared to other tools in our industry. To spend a little less money, and a lot more time to create something that will under-perform, this is called an expense, or a liability. Your choice, though. This is just an offering of experience mixed with honesty.
If you're gonna fabricate your own gear, create stuff that doesn't exist yet.