However flying around for a 100 hours seems really really hard for me, I would find something useful to do.
My line of thinking.
GOT, You're saying you only need the hours, so that indicates you don't need to improve your maneuvres etc? FW pilots, OK, they don't have awful much to do after getting to grips with PPL, presuming their navigational and instrument flying is at high standard, so they opt for extended XC flights daily in Florida to meet requirements to do CPL course, pronto.
I'd get bored doing so many extended XC flights in helicopter in a row (at least in R22 with sissy trim) to have 100 hours out of them.
I'm not sure the school would allow you to do all sorts of maneuvres incl autos flying alone without their CFI.
When I asked one guy doing his training towards CPL, in the lines of 'why don't you fly lots of solo XC to get more time in fast', he replied he'd rather pay bit more for instructor as there's always things to learn. Besides doing all the maneuvres to proficiency for CPL and CFI later on. Much more solo XC than required, hmm, not sure many actually do that around here.
At least in Hillsboro Aviation, renters aren't supposed to do bunch of maneuvres that are practised with CFI in pattern. Maybe I remember what solo flights towards PPL should/shouldn't do. Not ar**d to check the limitations in logbook.
Someone mentioned elsewhere that Bristows aren't likely to accommodate renters wishing to fly bulk of hours solo with their busy aircraft. Fella I know who just started his J1 at BA wrote he's glad he's got his PPL done in R22 earlier so he doens't have to compete for time in Bristows busy Robbies (after all, US CFIs need 50h in R22 and 200TT to instruct in line with SFAR73)
EDIT: Whirly I checked out NAC and Starlite yesterday after you posted something about them in different thread. I looked into SA in the past, but unless someone wants the environment, the strength of Rand in recent years doesn't help. I ran the SFH rate incl fuel in R22 from one of their website and it's actually more than dual in most US schools. Flights aren't likely to be less. Maybe they've got better deals for 100h 'block', but as of now, it's not really cheaper than USA. Just like OZ or NZ regular rates..