I just lost a large response from a system crash. Damn. So I'll do a short one here.
Just recently I see an episode of Antique Road Show with a low serial numbered old Mac 128K on it and the guy appraised it for $4000 as is. If it could turn on (he forgot his power cable- LOL!) and had the original floppy disks and booted, it would have been appraised for $5000 to $8000. Another Mac they appraised was a Mac SE in a clear case from Apple themselves, it was a demonstration and research model where only 200 or so were made. it appraised for $10,000 in bootable and working order (they did not turn it on for some reason). The 'owner' said he got it from an estate sale from some Apple employee a few years ago for couple hundred dollars. Damn!
I had a Mac SE\20 (a Mac SE with a '020 accelerator at 25MHz), and I will say that is was wickedly fast. But it was not so fast that it was terrible. It was more like a Mac IIci or LC III. Many of the routines that it does are either in ROM or in RAM. My Mac IIci with the DayStar 50MHz '040 is as fast and at times faster than my Q950! And it is definitely faster than my Mac IIfx which has a 40MHz '030. But putting an accelerator into the machine, it is no longer stock. It is faster (and better) than the original machine it started out with. Everything on it will be faster on it. So depending on the accelerator, it will be as fast as a Mac IIfx and probably as fast as a Quadra 900/950 as these were the fastest 68K Macs around. So that video you saw is up to par with what your Mac SE\30 would be doing.
The CF or SD to SCSI adapter is just an option. Since a CF has a micro IDE interface, you can get a IDE/ATA to SCSI Adapter or Bridge and use a IDE/ATA Drive. They still make 20GB IDE/ATA hard drives but do you need one for a SE\30? Anything smaller would be considered as NOS equipment.
Just recently I see an episode of Antique Road Show with a low serial numbered old Mac 128K on it and the guy appraised it for $4000 as is. If it could turn on (he forgot his power cable- LOL!) and had the original floppy disks and booted, it would have been appraised for $5000 to $8000. Another Mac they appraised was a Mac SE in a clear case from Apple themselves, it was a demonstration and research model where only 200 or so were made. it appraised for $10,000 in bootable and working order (they did not turn it on for some reason). The 'owner' said he got it from an estate sale from some Apple employee a few years ago for couple hundred dollars. Damn!
I had a Mac SE\20 (a Mac SE with a '020 accelerator at 25MHz), and I will say that is was wickedly fast. But it was not so fast that it was terrible. It was more like a Mac IIci or LC III. Many of the routines that it does are either in ROM or in RAM. My Mac IIci with the DayStar 50MHz '040 is as fast and at times faster than my Q950! And it is definitely faster than my Mac IIfx which has a 40MHz '030. But putting an accelerator into the machine, it is no longer stock. It is faster (and better) than the original machine it started out with. Everything on it will be faster on it. So depending on the accelerator, it will be as fast as a Mac IIfx and probably as fast as a Quadra 900/950 as these were the fastest 68K Macs around. So that video you saw is up to par with what your Mac SE\30 would be doing.
The CF or SD to SCSI adapter is just an option. Since a CF has a micro IDE interface, you can get a IDE/ATA to SCSI Adapter or Bridge and use a IDE/ATA Drive. They still make 20GB IDE/ATA hard drives but do you need one for a SE\30? Anything smaller would be considered as NOS equipment.