We will normally pre-test blanks in development without totally building them ...
Have done this many hundreds of times as a matter of course.
We use EVA casting rod grips of various lengths that can snugged on and off, snug the reel seat with under wrapped painters tape ...
... Secure the guides with automotive detailing tape onto the blank, hot melt glue on a tip top, and go casting.
Even had a short fight with a nice Rogue Summer Steelhead that got his teeth tangled in the casting yarn one time ...
Tore off several of the taped-on guides in the fight before he broke free ... };^) ... !!!
Rob is right <> If a blank MFG. states that their female ferrules will depend on thread wraps for integrity ... It's a very poor quality blank, and I'd not use it as it will eventually fail.
... But if still concerned: Try this <> We'll use a couple turns of nylon strapping tape at non-flagged ferrule sections to temporarily reenforce them.
This works just fine for the short haul.