It is not too big of a deal to drill holes in acrylics, BUT you can get into trouble - eg drilling wrong size hole, drilling holes eccentrically, or cracking the acrylic.
If you have some wood working experience, you can treat the acrylic as hard maple & use appropriate techniques.
To prevent the acrylic from cracking, I like to sandwich the acrylic in plywood so it is supported while you drill, & no plunging through with the drill bit.
To prevent drilling an eccentric hole, I would suggest using a Forsner bit, preferably in a drill press. Otherwise, you need to make sure that the drill is absolutely perpendicular to the acrylic & be careful to start the hole so the bit don't wander. Esp. with a cheap spade bit & a non vertical drill angle, you can end up with an ellipse hole & the bulkhead won't fit!
Also, you need to play with the drill speed as a hot bit will melt the acrylic & make a mess of the works. Best to practice on some scrape pieces before doing it for real.
80 gal FW with 30 gal DIY wet/dry/sump.
9 fancy golds, 1 hillstream loaches, 1 rubber-lip pleco (C. thomasi), 3 SAEs, small school of white cloud minnows, planted.