http://www.kan.org/6100 is the guru lore site for 6100 fans.
I would bump up the hard drive if possible, as that seems to be your biggest headache at the moment. A 500MB to 2GB 50 pin SCSI drive should cost next to nothing + shipping, if you hunt and wait patiently. 50 pin to 68 pin adapters are very cheap too, and would open up your options for cheap SCSI drives. If there was one single thing to spend a small amount of money on, that would be it IMHO, as it will take care of several of your other issues.
Upgrade to MacOS 8.1 and reformat your disk as HFS+. Use Symbionts or Conflict Catcher - both of which show far more items than Extensions Manager - in addition to the InformINIT database, to strip down your startup items to the minimum, to preserve your precious RAM. 68MB should be more than enough for 8.1, which has improved networking, improved 68k emulation, less 68k code in the OS, and HFS+ booting.
In fact, going all the way to 8.6 or 9.1 would help eliminate even more 68k code from the OS and speed things up considerably. Your current RAM should be plenty with some judicious INIT trimming. I ran 8.6 on my Powerbook 1400 which had less RAM than your system.
Anything less than 7.6.1 is a hair-tearing crashfest on PPC, in my experience.
The HDI-45 port uses main system RAM as video RAM, hence the insufferable slowness of video through that port. The only way to improve the onboard video is with L2 cache - 1MB of which will cache the entire screen, acting as if it is fast VRAM. Even 256k will help a bit at your resolution. As the 512k and 1MB sticks are unobtanium, the simplest way to get it is onboard a G3 accelerator, which will speed everything else up enormously as well, including AV/HPV video. But still, you don't want to spend any money, so for now stick with the video port on the AV card, which has its own VRAM.
In summary: if you are prepared to spend a very small amount of money, either LCGuy's network storage suggestion, and/or a faster, larger internal drive seem your best bets for an improved experience. If you have to pick one or the other, I would pick the latter. And my software/OS suggestions above.
An interesting challenge!
I would bump up the hard drive if possible, as that seems to be your biggest headache at the moment. A 500MB to 2GB 50 pin SCSI drive should cost next to nothing + shipping, if you hunt and wait patiently. 50 pin to 68 pin adapters are very cheap too, and would open up your options for cheap SCSI drives. If there was one single thing to spend a small amount of money on, that would be it IMHO, as it will take care of several of your other issues.
Let's take care of those issues together.
Upgrade to MacOS 8.1 and reformat your disk as HFS+. Use Symbionts or Conflict Catcher - both of which show far more items than Extensions Manager - in addition to the InformINIT database, to strip down your startup items to the minimum, to preserve your precious RAM. 68MB should be more than enough for 8.1, which has improved networking, improved 68k emulation, less 68k code in the OS, and HFS+ booting.
In fact, going all the way to 8.6 or 9.1 would help eliminate even more 68k code from the OS and speed things up considerably. Your current RAM should be plenty with some judicious INIT trimming. I ran 8.6 on my Powerbook 1400 which had less RAM than your system.
Anything less than 7.6.1 is a hair-tearing crashfest on PPC, in my experience.
I have heard that it's good to switch it on and put the amount of VM to the absolute minimum - it should almost never page out to disk, but it improves internal memory management somehow.
No. The AV and HPV cards will only accelerate video through their own port.
The HDI-45 port uses main system RAM as video RAM, hence the insufferable slowness of video through that port. The only way to improve the onboard video is with L2 cache - 1MB of which will cache the entire screen, acting as if it is fast VRAM. Even 256k will help a bit at your resolution. As the 512k and 1MB sticks are unobtanium, the simplest way to get it is onboard a G3 accelerator, which will speed everything else up enormously as well, including AV/HPV video. But still, you don't want to spend any money, so for now stick with the video port on the AV card, which has its own VRAM.
Apart from more space, a newer hard drive can also be faster.
Good suggestion. A SCSI Zip or even Jaz (1-2GB) should be only a few bucks, and easily transferred to a newer machine. It also gives you a simple way of swapping large files with another machine - especially if you also pick up a USB Zip/Jaz for the other machine/s.
In my experience, the exact opposite is true (see above)
Also a good suggestion. An adequate PC for the purpose should be more or less free.
That shouldn't be the case - in my experience they can be hunted down for $5-$10, tops, with a bit of patience. Someone here might even have a spare if you post a request in the Trading Post.
Even more reason to consider an external SCSI case
In summary: if you are prepared to spend a very small amount of money, either LCGuy's network storage suggestion, and/or a faster, larger internal drive seem your best bets for an improved experience. If you have to pick one or the other, I would pick the latter. And my software/OS suggestions above.