Windows 95 may be installed succesfully but won't be usable anyway. With my 68060@50MHz, the emulated PC is close to the level of a 286 CPU@ 16 MHz and the AGA video is of course slower than a native planar board (or is it chunky?).
If you want windows95 use a bridgeboard instead. With my A2386 upgraded with a 486SLC2@50MHz cpu, i have a setup equivalent to a 486DX33 according to Norton Sysinfo.
Either way, the best DOS version IMHO is MSDOS 5 that comes on 3 DD floppy disks. Windows 3.1 installs itself flawelessly on it. I prefer Windows 3.1 instead of 3.10 or 3.11 for workgroups, as you won't be using network with PC-Task anyway.
As for the partition problem, there is a specific mask to enter (explained in the PC-Task FAQ available from aminet). I remember i tried this once or twice and that sometimes the entire partition can not be recognized by FDisk. In this cas, destroy the partition and try again until the full capacity is recognized.
However, hardfiles are better IMHO for PC-Task, and you won't risk ruining your harddrive. Make sure to use a fast file system like SFS and a good amount of buffers.