I would like to revive your old thread Marc because I think it is important.
For big mounted 90 mm and 75 mm figures like this one, I think that we should not try to pin the legs as far as possible.
Because, by doing so, we are actually weakening the drilled legs since there is less metal remaining and most of the time, the leg will break a few mm higher than where the pin ended.
There is only one safe solution to this problem if the casting company has not inserted pins during the casting process.
YOu have to insert a thick stainless steel pin (not brass) going from the ground, through the horse belly and inside the riders body.
This pin should be thick enough to support all the weight of the figure so the figure is actually floating on its base but still in contact. Depending on the weight of the figure, it should go at least two inches deep inside the wood base.
This is the only way to insure safe transport and longevity to these big pieces. I would drill also the feet of the horse for inserting small pins but only 5-7mm deep or so.
Then you hide the main pin with grass, foliage, etc..