Sorry to butt in.
If you already have an iS133 and plan to keep it? Or replace it with an iS150/HWR
If you are keeping the iS133, then it must surely be sensible to get the HWR or LWR to open up a very usable gap.
If you intend to swap the iS133 for either an iS150/HWR, then I'd go with an iS150 for it bigger usable range.
Like Remi say's, the only down side to having a HWR/LWR is that your 9.7m is considered a "high wind" formula sail. SB formula's from FW161 onwards like big powerful sails, so it might not feel 100% right with a 9.7m. The 9.7m on iS150 would be considered a light wind sail and would work very well.
Early planing, the FW147 tail width at 74cm is pretty narrow by today's standards, 80cm plus is normal now. The 147 still has a wider tail than the iS150, but it also has more nose rocker on the iS150, the iS150 has a very wide and low nose which assist in early planing. I'll stick my neck out and say you will only loose about 2 knots of wind on the 147 Vs 150 thing.
Unless you have won the lottery
an iS133 and iS150 would be real luxury. iS133 and A HWR would be perfect if you live in a low wind/inland water spot. But, it would definetly be worth while trying to get hold of an 11m sail to get the most of a HWR.